I've shot deer (and elk with most of these) with:
.243 Win
.25-'06 Rem
6.5 Creedmoor, .260 Rem, 6.5x.284 Norma (still a wildcat when I killed a bunch of deer, pronghorn and elk with it)
.270 Win, .270 Wby Mag
7mm-08 Rem, .284 Win, 7mm Rem Mag, 7mm Wby Mag
.308 Win, .30-'06 Springfield, .300 Win Mag, .300 Wby Mag
.338 Win Mag, .340 Wby Mag
By far the most impressive killers were the .25-'06, 6.5x.284, .270 Win and .270 Wby Mag on both deer and elk. Lightning bolt kills from all of them with bullets that are considered light today.
Given a choice today, believe it or not I'd take my 6.5 Creedmoor loaded with factory Winchester Deer Season XP 125gr bullets for whitetail every day of the week. Every bit as impressive as any of the above and way less recoil and muzzle blast. So easy to shoot well and so, so effective.
There is a soft spot in my heart for both the .25-'06 on mule deer and especially the 6.5x.284 on all deer, speed goats and elk. However, it is just so much easier to live with a 6.5 Creedmoor shooting factory Winchester 125gr Deer Season XP and Winchester Expedition 142gr ABLR.