This is a list of different things you can find all in one topic that doesn't require you to go Traversing the forums.
How to find:
Aether: Pick up apple cores, banana peels, cans, clumps of pipes, cogs, screws, and springs, blow up propaganda carts, refreeze scorpiston and cogra nests ( just normal ice), refreeze croc nests (Vapor Condensor or snowglobe), Smash the jiggly wiggly propellers on the Flying L (hammer), repatch holes on flying L (fabric patch), repair wind socks in southern slurries (fabric patch), taking down (bad) posters, and, or, putting on new ones.Picking up Solvent does NOT give you aether
Feathers: Put petals on the fake bird's food plate. Violet Petals: Pink Feathers. Fire Petals: Fire Feathers.
Petals: Get petals after planting a plant and watering it
Plants: Lukas' place I don't know anywhere else.
Water: I know there's one in Bootleg Pass and possibly the flying L
Oil: NML , Flying L, Grease Vats.
Steam Cans: Lukas', Flying L
Ice Flowers: Put ice on cacti wait at least 24 hours
Croc tears: Put vapor condenser or snow globe on croc nest and wait 24 hours
Venom: Put ice on cogra eggs and wait 24 hours
Fur: Put ice on any type of nest and for the top two it will give you one or the other.
Bananas or apples: Go to flying l shop stands and trade with the people of the shop stands
Sno-cone: Put 3 ice on any snow cone machine and be ready to give something like 5 cogs.
Ballons: Right beside Rose and Lily on Flying L
Metal Patch: Put can in PatchMaker3000 right beside Rose on the Flying L and you get 3 metals patches
Fabric Patch: Same thing but with balloons
Anyone can add anything else!