Feel like I'm way behind in gear for how much I've progressed in Silksong. Any spoiler free pointers on areas I should search more?

For reference, I have just beaten >! Cogwork dancers !< (Early/mid act 2 boss), but whenever I talk to anyone else playing the game, I realise I've found very little.

The only crests I have are hunters and wonderers, and the only silk spell I've found is silk spear. I've only found 1 simple key (the one sold by Pibb in bone bottom), only gotten 1 silk heart, 4 mask shards, and 4 spool fragments.

I've got what I think is a reasonable amount of charms and gadgets, but I'm not sure. Got about 4-5 in each category, but I know there are some other helpful ones I'm missing.

Please could I have some vague pointers on areas I should explore more or anything else I should do to find more of these things?