A few cool things from the RBY transfer:
- Body Slam + Quick Attack Tauros (Body Slam has been covered already but QA is cool STAB priority, although might have a hard time finding its way on movesets)
- Leech Seed Vileplume (Debatable whether this is worth using over Sleep Powder but could work)
- Growth 1st gen Eeveelutions (Z-Growth gives you +2 SpA boost and gives you an opportunity to go mixed, Jolteon gets a shoutout due to it being fast and having BP if that's ever unbanned)
- Sweet Kiss Politoed / Poliwrath (putting random mons to sleep is fun)
- Petal Dance Golduck / Jynx (Bloom Doom beats bulky Waters for Golduck / Waters and Rocks for Jynx)
- Petal Dance + Sing Raichu (Bloom Doom beats bulky Grounds, Z-Sing is an interesting concept, too bad you can't run both Z-moves)
- Rapid Spin Golem (Less outclassed by Rhydon ig)
- Hypnosis Misdreavus (Z-Hypnosis Mismagius seems cool)
- Ancient Power Venusaur (Continental Crush gives you 120 BP Rock coverage)
- Sharpen Steelix (Z-Sharpen gives you a SD boost)
- Sweet Kiss + Rock Throw Pinsir (Continetal Crush is good coverage and confusion is there if you want to be gimmicky)
- Mind Reader Mr. Mime (Z-Mind Reader gives +1 SpA and gurantees you can hit something like Focus Blast)
- Safeguard Xatu / Stantler (Z-Safeguard gives +1 speed)
- Sweet Kiss + Lovely Kiss Victreebel (As mentioned before, random sleep is fun but you should prob only use this over Sleep Powder if you are looking really weak to a Sap Sipper mon. Sweet Kiss gets a shoutout because Z-Sweet Kiss gives you a +1 SpA boost allowing you to make use out of your special movepool)
- Agility Magneton (Could function as a good sweeper, has good power and bulk and 70 speed is not bad for an Agility sweeper)
- Pursuit Electabuzz (Pursuit's busted)
As you can see I got a bit lazy toward the end. Also some of these mons are speculative but there's a good chance we'll get mons like Venu and Magneton I hope. I'm also operating on the presumption that Electivire and Mismagius will get Pursuit and Hypnosis, respectively.
Thx for reading + hope this was helpful!