Like almost everyone in this hobby I too had a steel collecting phase. Spyderco are mainly to blame for scratching that itch, as they are one of the few that experiment with new (to knives) steels.
It all started with a Tenacious below are the steels in my collection in no particular order.
8Cr13MoV
VG-10
1.2379 (D2)
154CM
S30V
S35VN
S90V
S110V
K390
M4
M390, 20CV, M390MK
Maxamet
Magnacut
Rex-121
CTS-XHP
1075
As an urb*nite who rarely goes camping, most of the steels above are on folders. 1075 is on a Condor Kukri, but nowadays I prefer carrying a small Husqvarna axe instead but I have no clue what the steel there is so it isn't listed. Most of my other fixed blades are by Manly, small to medium sized, all in 1.2379 and the latest being a small one in Magnacut.
I feel like I am sorta out of the "gotta have all the steels" as I've more or less figured out what I like in a steel. Not by choice most of my knives are in M390 variants, I'll prioritize an appealing design and comfort over steel, they just happen to come with a good steel as well. My favorites include
M4
K390
VG-10/154-CM
S35VN (in CRKs)
CTS-XHP
Magnacut, Maxamet and Rex 121 are way too new to my collection, but after getting the Rex 121 Sage 5 I'm really liking the edge retention.