Many updates add bugs to the game- but these bugs are so frequently taken out by the determined developers! It would be neat, (In my opinion), if there was an update devoted to adding bugs... if only because the opportunities for puns would be endless. The environments of the Overworld are, in my opinion, somewhat static- and the addition of colorful beetles that would also serve a practical purpose would be a welcome one. (I go into this in more detail in This Thread)
Insects would not have to be complicated- these would be small creatures about the quarter the size of a block, that would fly away a short distance when players get too near. If determined, you can use a glass bottle to catch and release insects- which can be bred, and frequently drop dye when killed. Different colors of beetles would spawn in different biomes, and, like sheep, breeding different colors together might result in secondary colored variants. Some beetles might have flowers or mushrooms growing from them which could be removed with shears, and would then regrow- making these otherwise irritatingly elusive items farmable. Finally, this would, (Of course, add some new enchantments & potions involving beetles. Bottles of beetles could be used as brewing ingredients for things such as a levitation potion that would cause the player to levitate briefly before the end of a fall that would cause damage to them, or a Potion of the Beetle Master that would turn all nearby beetles into helpful allies that would attack hostile mobs. A Lord of Arthropods enchantment would make spiders, beetles, and silverfish friendly- and, in higher levels, might result in turning these creatures to fight for you.
Other ideas: a new armor/tool set that required 'Phase Plating,' a resource made with eight phantom membrane and a beetle shard that could be used to craft elytra, and make a special, end-game armor set comparable to netherite that would offer special abilities, and possibly require ender world materials to craft.
And, last but not least, a Better Beetle Bottle that is even more difficult to pronounce than the first one. By combining nine beetle bottles in a crafting grid, you get eight empty bottles and one better beetle bottle that would release nine beetles when used- a powerful tool when used in combination with Lord of Arthropods.
...It's an idea. I think adding these small creatures would both serve to give more life to otherwise static environments, and could also serve a practical purpose towards game play.