So... first off, I love this mod, the idea of giving hats minor passive boosts is great!
But with that said, several hats currently have balance issues that make them way too powerful:

• Unsure if visual glitch or not, but the Bowler Hat appears to give infinite speed (the speed buff icon constantly flashes while running and can often stay on screen while not moving)
• Bunny Ears offer way too much jump height
• Slime Hat completely negates fall damage... most of the time. This makes it incredibly powerful since there are so few ways of stopping fall damage in Minecraft
• Cowboy Hat has a nice bonus, though it could be toned down ever so slightly
• Floaty Hat offers inconsistent fall damage negation, as it seems to stop working randomly
• Dome of the Strider doesn't seem functional currently, but fire resistance as a passive boost would of course be incredibly powerful
• The Woolrus combines a potion effect and an effect obtained by mobs, a bit overtuned
• Space Helmet provides infinite water breathing passively, making it more powerful than water breathing potions and turtle shells combined
• Leprechaun Hat providing the luck buff might make it too powerful when exploring, as the buff boosts gear quality in newly generated areas
• The Golem Bucket's effect is funny when it triggers, but the effect may be sending mobs too high up!
• Jotaro's Hat applying weakness to mobs makes it almost a necessity in combat, as this effect is hard to come by normally
• Dwarven Helm is incredibly overtuned for mining underground, especially when one has an enchanted pickaxe
• Awesome Shades give an entire minute(!) of night vision just for crouching, making them incredibly powerful in just about any situation that the other night vision-based hats could be used in, and basically offering infinite triggering of a potion effect

There are some hats I didn't list as their effect is rather fitting (albeit a bit overtuned in some cases).
The issue with these hats being so powerful is that it becomes less a choice of vanity and more of "which overpowered passive boon do I need in this situation?", which takes away from the whole point of hats, which is to look fancy!
There's also the issue of hats dropping so often - you end up having multiple hats and often a lot of duplicates after just a few villages or outposts. This can thankfully be adjusted to some degree in the configuration, though the default should probably be toned down.

What I'd love to see happen is to have some of these hat effects reduced as much as possible and even completely replaced in some cases (Woolrus comes to mind). Hats should provide minor stat boosts and such, not be game-changing buffs the way potions and enchantments are.
And most importantly: an option to make the hats function purely as vanity items would be amazing.
Thank you.

Thank you for the constructive response! Understandably balancing bonus items like this is always going to be a subject of debate and personal preferences.
I suppose the general question to ask is "how does this hat compare to the other hats?" when finding a happy medium for power levels, as that will allow balancing the hats with themselves and avoid a situation where one hat is the only option at any given time.

Finding powers and abilities that make each hat unique is tricky but can go a long way in making them more fun to play with.
As an example, Cat Ears provide a unique and interesting gameplay bonus with the sneaking to scare away creepers, but then the incentive to play with them is lost when other hats provide general potion effects that tend to be much more powerful.
What if the Dwarven Helm made mining only metal faster, for example? Or the Space Helmet provided longer underwater time like the breathing rod in Terraria, there's ways each hat can fit a niche that makes it worth collecting without upsetting gameplay too much, at least in my humble opinion!

With regards to luck; the Luck of the Sea enchantment gives the player a "luck" attribute which is indeed scaled by the Luck buff, while the Luck buff also affects general loot quality in the world - more specifically the bonus rolls (chances of more loot appearing in chests) in newly explored chunks.

Night vision is one of those funky cases... what if the Awesome Shades made it possible to look at Endermen without aggroing them, similar to pumpkins but without the screen overlay?

I'm glad to hear a vanity option is planned, I can imagine with the number of hats available already it would be a tad tedious!

thank you firstly, if you don't mind I have some responses to here, (perhaps this is a bit like a debate lol)

• you get speed for 10 ticks with the bowler hat, so yeah probably a visual glitch, the idea is you do get it forever tho
• I do tend to find low jump boost doesnt add so much to the game but perhaps it could be less
• yeah the slime hat is suppose to act as if you landed on a slime block, its like the slime boots from tinkers (which did the same thing)
• I struggled with the cowboy hat to make it noticable but also not make you literally start flying, could probably be toned down lol
• floaty hat only gives you slow falling when you have fallen 2 or more blocks, kinetic damage probably builds up somehow so thats probably why it doesnt trigger
• strider hat gives you fire resistance if you don't have fire resistance, I believe the particles are hidden however
• I kinda wanted to emulate dolphins with the woolrus hat, but I suppose it doesnt need the night vision
• not really sure how id tone down the space helmet without excess items
• currently only fishing uses luck (or it was the last time I checked) and tbh i think its an underused effect
• the awesome shades give a minute of night vision because if it gave you seconds youd get that really annoying flashing effect

Id argue that this mod kinda fits into the ProjectE category of "overpowered but fun", perhaps what might be a solution is instead having a universal "amplifier" that can be numbers smaller that 1, that then can reduce or increase the default values of hats so that people can modify it easily, I think that would help for the people who do want op hats but also the people who want cool hats that do small things

making the hats purely for vanity has been mentioned before actually, eventually ill get round to that as a config option because its a pain changing a bunch of if statements lol

and ah yes, the spawn rate of hats. I recently changed the way hats spawn to inject them into every structure because then it works more consistently on forge and fabric, there is quite a reasonable chance that needs to be turned down

again, thank you for your feedback, and im not trying to be scathing here, I think its good to talk about balance features because when it comes down to it, a lot of them do become opinion :)