In the absence of an official dedicated “Tool / Resource” area of the app - the “Notions” area is where I choose to record information about things like presser feet / machine attachments / sewing books / tools & gadgets / reference information.
You could even use this idea 
to record 
links to your online sewing classes or courses that you have bought / 
wishlist.
Forum user @JD3205 already does something similar (great minds 
think alike huh 
) 
I have created several different custom-to-me “Notion types” to manage these for my personal needs…
ⓘ
APPENDIX Reference Information
(where I upload picture/diagrams of things like Zipper sizing nomenclature, Cup sizing, bias tape widths)
Presser Feet & Attachments
Stationery Supplies
Tools & Gadgets
(non-consumables e.g. Hammer, thread colour shade card).
NB: I’ve noted that whenever I add an emoji in the app to the beginning of the name of something it will automatically place that name at the bottom/end of the alphabet AFTER “Z”. So, I use it as a way to place the special-to-me names of things (including my custom Tags) at the bottom 
. This makes it easier for me to find 
🕵🏻♀ them amoungst my zillions of “true” Notions (such as Buttons, Zips, Ribbon etc.).
There is an existing item on the Roadmap called Add a notes/resources section #73
Quote: This would be for things that aren’t tied to any records. E.g. how someone has decided to structure the app
But, I dunno if/when/how that item gets rolled-out “if” it would work for things like presser feet / machine attachments / sewing books / tools & gadgets / reference information…soooo in the meantime I’m happy doin’ what I do with my way above 
.