Team of six

Tangela/Venusaur/Ivysaur with VW/SoB
Piloswine with PS/A
Starmie with WG/HP
Wigglytuff with P/DG (I think that's the moveset you want... don't remember)
Machamp(/Machoke if possible) with C/DP
Scizor with either double bug or double steel moves.

Wigglytuff was the best prestiger from gen1 overall (great generalist) and the buff to DG should help improve that.
Piloswine appears to be the best generalist from gen2 (although anything that resists Ice he won't work for). PS generates SO MUCH ENERGY and Avalanche is one of the best charge moves (90 damage for 50 energy).

Grass, Water, Fighting, and Steel types round out my top 6 for type coverage. An electric type may make it in there if Gyarados is common on your team (I do prestige a lot with Jolteons). I also don't have the fighting or steel types I mentioned above.

Tangela for Vaporeon, Seadra for Rhydon, Jolteon for Gyarados, Raticate for Exeggutor or as a generalist and Jynx for Dragonite. I will switch it up occasionally, but the above is my most used. For Snorlax I may use a low level Vaporeon though I don't like putting so many potions into prestigers

Haven't tried Wobuffet, but Furrett was surprisingly good (and plentiful!). Xatu wasn't stunning but usable (again common round here). Muckrow was very disappointing as was Aipom.

According to my research (and not yet field tested), Hypno, Exeggutor, Slowking and slowbro with Confusion are good. Ampharos, Electrode, Jolteon with Volt Switch do similar although are better to attack the current meta.

For fast/charge combos:
blissey with HB most notably the pound version (DG was notable too)
umbreon
steelix - iron tail

can't remember what else, although I eventually realized that with the recent change to the attack speed, a lot of mons can defeat their 2x CP counterpart with effective dodging and STAB and/or SE moves/movesets.