Knife collecting is a popular hobby but I don't think it's going to last, I've only been at it for a little while and am beginning to get bored with it.....
NOT!!!
Jk, my best advice to you is 1) buy what you like, 2) don't collect for investment is hard to profit on knives, sometimes you get lucky but always remember rule #1 and you always at the very least have a knife you like and most likely use.
Finally 3) pick an overall direction for your collection, don't become an accumulator unless you want boxes of knives that are totally unrelated other than the fact that they ask have at least one sharpenable edge.