I agree with PK, after the obvious top 2-3 most collectable k98ks, its entirely subjective.... But
Here's my list. Top being best, most valuable and collectable.
1) All matching mint bore Vet bring backs. No duffle cut, no sanded stock, etc. No issues. No import marks. Rare codes/contract rifles at a premium.
2) All matching vet bring backs or all matching old imports (discreet barrel "germany" stamp) with small issues (lightly sanded stock, duffle cut stock, good bore, worn bluing, etc)
3) Vet bring backs all matching with non matching but matching to itself bolt.
4) Original Stock cut down but otherwise all matching metal complete Actions, bolt, TG etc. Big plus when the original stock parts come with the rifle. Known as "Candidates for Restorations". Say what you will but the matching metal is the real deal original German "as left the factory" 98k and that beats a total mixmaster or refurb any day.
5) Norwegian post war reworks
6) East German reworks
7) French Reworks of course excluding the rifles produced by MO for the French after they captured the factory (those are close to the top in collectability)
8) Czech post war 98k's (mint examples with non-scrubbed receivers are superb COLLECTER'S pieces and they scream quality)
9) RC's (because of all the added possible cold war history and current market values)
10) Balkan imports (Albanian mostly, unpeened, and only if the bore is good or better)
11) Yugo reworks (usually the bores are mint and make for great tack drivers)
12) Iraqi Reworks
13) Israeli reworks
14) "unrestorable" sporters (original barrel gone, bolt handle bent in a figure "8", drilled through receiver for crappy mounts, etc) Regardless still shoot well.
15) Mitchell's mausers, Bubba special horror jobs, "humper specials" (all the same to me, $50 is what I would pay if that)
I will add that repro 98k snipers deserve a place as well, but they are very subjective value wise. Personally I think they are worth the sum of the parts plus some extra for quality of Gunsmithing work performed.