i prefer to try to get the collectibes myself rather than buy or get them from others most of the time, which means i tend to complete them slower. i still think i got a decent amount tho :)
the ones i completed are: postcards, hotw, doodle pages, backpack pins and all the event collectibes. so that's 7/11 and for the others i haven't completed i only have 1 or 2 items left at most (except for those pesky snowflakes)