Lee Enfield, Mosin Nagant, M1 Garand, K98, Carcano, SVT40 and Arisaka 38 or 99.
All of these would have been combat rifles in WW2. The Japanese rifles being harder to get. Rest are available when one looks for them.
Other choices that would be of the period that wouldn't have been used in any major form.
I think that list can be expanded on...
Lee Enfield should include both a No.4Mk1 or Mk1* and a No.1MkIII*, either Indian or Australian or British dispersal rifle.
You could look for a finnish Mosin like an M39 or M91.
Agree on carcano, and specifically an M38 TS or moschetto or an M41.
SVT38 also a possibility.
Any of the Gewehr 43 variants would be a nice addition, or if you can find one, a volkssturm VK series 1 or 2.
M1 carbine, M1903 or M1903A3 should be on your list, not just the M1.
French Berthier Mdl 16 rifle or carbine, or an MAS 36.
Austrian M95 converted to 8x56R
VZ24
Serbian M1924
Belgian Mauser Model 1889, Mauser Model 1935, and the FN Model 1924 and 1930 are all good choices.
Chinese chiang kai shek mauser (usually based on the VZ24)
you could consider a P14 or M1917 - both saw extensive WW2 use.
Greek
Mannlicher–Schönauer Y1903/14
Norwegian Krag.
I 100% disagree with people saying to get a Swiss or Swedish rifle as a representative WW2 rifle. Like Turkey, these countries were NEUTRAL. Their rifles fired no shot in anger during the war. They are interesting milsurps, I own some of each of these - but I do not consider them WW2 rifles.