This is actually an expansion of an idea I posted on the old system, "bug 4820". Some of the ideas are copied from there.

Right now, there's three types of blanket - plain, waterproof, and fireproof. Two really only serve a purpose for protecting the pack, and the third doesn't really serve a purpose at all (yes, you can use plain blankets to cover pits, but why do you want to hide a pit?).

As such, I've come up with some new ideas for other blankets, some of which serve as protection for the pack, while others are intended for use in other ways. I'll list them by number.

1. Lightweight blanket - alters the weight of items in the pack by -10%/-5%/+5% if B/U/C. Multiple blankets only partially stack, with the effect decreasing with each successive blanket (perhaps 25% less than the previous blanket).

2. Yggur's Seamless Blanket - this artifact blanket serves as fireproof, waterproof, and lightweight blanket all in one. Due to artifact nature, it gives perfect protection in the ToEF for all items in pack. It also decreases the weight of the pack by 10%, as a separate decrease from the lightweight blanket stack. Can also be worn as a cloak, in which case it protects both equipped and pack items, and increases PV by +3, but reduces dexterity by 5, due to difficulty keeping it on. Intended to be kept in pack.

3. Diseased blanket - this rare, nasty blanket curses all food items in pack (perhaps taking a few turns, progressively, to do so), and has a small chance of turning a potion into a potion of sickness - maybe 0.001%/0.01%/0.1% based on B/U/C status. Can be turned into a plain blanket by dipping in potion of booze (using alcohol to disinfect) or any of the 'healing' potions.

4. Concussive blanket - Protects pack items from destruction due to concussive forces (runes on doors exploding, mostly), but 30% chance of being destroyed in the process. Does not affect other types of item destruction. If worn as a cloak, raises PV by 1.

5. Ultra-soft blanket - reduces chance of item damage due to things like ceiling traps, explosive runes on doors, and the fall in the rift. Reduces by 30%/15%/0% based on B/U/C status. Effect does not stack (uses only best blanket), but may be destroyed while absorbing the impacts. Can be worn as cloak, in which case it reduces PC damage from fall down rift by 10%. Very rare. (Thanks to Fizzle for making the comment that gave me the idea for this)

6. Orderly blanket - when in pack, alters corruption from artifacts in pack that contain the essence of Chaos and Corruption by -10%/-5%/+5%. Effect does not stack with multiple orderly blankets. Can also be 'U'sed when sick, and it will significantly reduce sickness (even cure it, if it's a mild case), but has a 50% chance of turning into a diseased blanket when used in this manner (if it does, it falls to the ground, discarded). Logic being, orderlies work in hospitals. Yeah, kind of a pun. (Thanks to PORCO for basic idea)

7. Picnic blanket - reduces rate of rotting of food stored in the pack (great for carrying corpses, especially with food preservation skill also factored in). Eating food when standing on a picnic blanket requires 10% less energy.

8. Fine blanket - sells for a high price.

9. Itchy blanket - slightly increases (2%) energy required for actions. When not fighting, causes message "You scratch idly at your back".

10. Beggar's cloak - a blanket, greatly reduces chance of finding money around, but when worn as a cloak, some friendly generic NPCs will give you money when talked to. Can be given to a beggar for a very slight Lawful boost. If cursed, small chance that talking to a generic NPC will make them hostile.

11. Holy blanket - If dropped on an altar while blessed, positive piety effects are increased by 10% and negative effects are decreased by 10% when using that altar. Uncursed/cursed holy blankets have no effect in this context. Cursed holy blankets in pack will cause piety drops due to prayers and impious actions to be increased by 10%. None of the effects stack with multiple blankets. Uncursed and blessed holy blankets will not be destroyed by a god when punishing by destroying inventory.

12. Tattered blanket - when in pack, 0.1% chance of item falling out of pack onto ground each turn. If that item is breakable (all potions, some wands, some tools, and all gems), small chance of item breaking when it falls.

13. Child's blanket - Giving this to a child (including dwarven children) provides a small lawful boost, and 50% chance that child will give you a piece of candy in return.

14. Blanket of modesty - if worn as a cloak, Ap+3, Ch-5, Dx-2. Autocursing.

15. Electric blanket - If blessed, reduces pack item damage from electric discharges/bolts/breaths by 20% (effect halves with each successive blanket - so 30% with two, 35% with three, 37.5% with four, theoretical maximum of 40%). If uncursed, no direct effect. If cursed, will occasionally "overheat" and damage some pack contents. Turns into a plain blanket if exposed to water (can be done intentionally with uncursed potion of water, but mostly occurs from water traps/swimming/breath - use of waterproof blanket greatly reduces risk of this occurring).

16. Invisible blanket - rare blanket, if 'U'sed while standing on a pile of items, it will protect those items from being picked up by anything that cannot See Invisible (and significantly reduce likelihood with NPCs that can see invisible) - but if you can't see invisible, you'll need to remember where they are, in order to find them again. Could perhaps also be used for a new random dungeon feature - the hidden treasure pile. The pile will, naturally, include the invisible blanket itself, and has items generated at a higher "danger level" than the level that the pile was generated on. Can be found randomly (but very rarely), in which case it is visible. Cursed blankets are only invisible to the PC, while blessed blankets are invisible to all NPCs. Can be worn as cloak, giving DV+2 (cloak causes foes to find it harder to keep their eyes on you when you wear it).

17. Blanket of wishing... OK, this one's just a joke.

18. Magic blanket - very rare, much like a magic carpet, in a way; if blessed and placed in the tool slot and 'u'sed (can't just be 'U'sed - must be in the tool slot), allows PC to travel over a short series of traps without triggering them. Can also be used to cross short stretches of water (three spaces of water only - doesn't work over the water in the tomb of the high king). Uncursed blankets will activate, but not actually stop the traps from triggering (but will still allow PC to cross one space of water), while Cursed blankets will actually make every trap trigger when trying to cross (negates ability to avoid the trap, too), and attempt to use it to cross the water will cause double damage from drowning.

Some blankets get unID'd descriptions, others appear as simply "blanket". In addition to Fireproof, Waterproof, and Plain blankets, the Electric blanket, Blanket of modesty, and lightweight blanket would all appear as simply "blanket".

The rest of the blankets would fall into these groups:
1. "old" and "worn" -> Holy blanket or Tattered blanket.
2. "colourful", "patchwork", "patterned" and "tartan" -> Child's blanket, Beggar's cloak, Itchy blanket or Picnic blanket.
3. "green", "yellow" and "brown" -> Diseased blanket, Concussive blanket or Ultra-soft blanket.
4. "white", "clean" and "silky" -> Orderly blanket, Fine blanket, or Invisible blanket
5. "persian" -> Magic blanket.
6. "warm" blankets would always be Yggur's Seamless Blanket

And as the name suggests, Yggur's seamless blanket can be given to Yggur. In return, he will teach you Cooking, Survival, and Food Preservation - all abilities that would be useful in the wilderness (I figure that he spent a lot of time living out of the small cave, going into the wilderness for food, which is why he knows about the 'proofed blanket - and why he's now always drunk and semi-crazy). If you know any of the skills, you get a random potion in place of that skill (so, if you know all three already, you get three random potions. One, and you learn the other two and get a random potion).

The blanket would be given a guaranteed location - perhaps it could be found in the small cave, but only once the PC reaches level 15 and has spoken to Yggur. In this case, the blanket found in the small cave will be the artifact blanket. If you go into the cave before you reach level 15 and then speak to Yggur, the blanket remains the ordinary 'proofed blanket (perhaps there's a 5% chance that it's a lightweight blanket instead of a 'proofed blanket). Giving the blanket to Yggur would result in the message "You reunited a fool with his lost possession" in the memorial file. Of course, it's up to the player - they may prefer to keep the blanket for its protective and capacity-increasing qualities. The challenge, of course, is getting the blanket from the Small Cave with a level 15 PC, given the nature of the small cave (and since you can't go into the cave before level 15 if you want it, all monsters will be generated to suit a level 15 PC).