Unexpected potential surprises on Attackers Tier List?

I don't think blastoise or tangela will be included, since their stats are too low. They do still make excellent prestigers. I don't expect starmie to be included, and probably not feraligatr, either. If you want a water attacker, vaporeon or gyarados is the way to go.

I do expect to see venusaur on the list. Some people prefer venusaur over exeggutor for plant moves, since venusaur's moves are faster. Also, I think pilowswine will be on there somewhere. Machamp might be in the highest tier as a chansey and snorlax attacker. Scizor might be on the list as an exeggutor counter.

Rhydon borderline? Nope, even with the fighting move buff.

Exeggutor god tier? Yes, because of the buff of Solar Beam.

Vaporeon very good tier? Well, still OK.

Where is Alakazam?

Where is Vileplume/Victreebel?

The methodology for defender rankings mentioned a strong pokebattler sim component, so their rankings should give some insight in to expectations, which are below:

Gets Through Most Defenders
1: Blissey (far above others)
2-5: Tyranitar, Dragonite, Snorlax, Vaporeon (order depends on dodging strategy)
6-9: Gyarados, Rhydon, Lapras, Golem (order depends on dodging strategy)
10-12: Machamp, Exeguttor, Omastar (order... )

Fastest:
1-2: Dragonite, Gengar
3-4: Alakazam, Machamp
5-7: Tyranitar, Espeon, Exeguttor

Boosts Due to Being Especially Useful In Current Gym Meta
Vaporeon, Tyranitar, Machamp

The exact order depends on how various categories like those above are weighted. One possible order is:

Tier 1: Dragonite, Tyranitar, Vaporeon
Tier 1:5: Blissey (not 1 because has a key flaw)
Tier 2: Machamp, Snorlax, Gyarados
Tier 3: Exeguttor, Gengar, Alakazam, Rhydon, Golem , Lapras

Lanturn will certainly be there somewhere.
Probably the only gen2 besides Blissey and Tyranitar.

If they take the Water Event into consideration, based on the fact that everybody will have one or two more Gyarados, I would say crank up every good electric pokemons one step up, so that would likely put Jolteon closer to the top. Not elite, but suddenly most wanted in tiers 1.