The people putting up Incineroar and Melmetal (look like strong pokemon), need to look at Torterra for a second.
Turtwig/Grotle had plenty of wins under its belt. No reason to doubt it strength after it evolved. Then it was pitted against powerhouse after powerhouse after powerhouse in the part of the series where Infernape's story needed to be resolved (Blaze resolved vs. Volkner and obviously the star vs. Paul).
The truth is, both Incineroar and Melmetal have little to show for themselves and this is due the anime handing them late evolutions. We know Glalie is strong because it tore up the Hoenn League after it evolved. Meltan had a joke win, a loss vs. Silvally and an okay win vs. Empoleon (arguably the least hyped of Kukui's team). In my eyes, outside of something abstract as "potential", there's nothing pointing towards putting it above Torterra. Because if we're talking about potential, then Torterra could probably still swallow an Energy Ball - and we saw what happened when Grotle used that technique vs. Palmer's Rhyperior. Torterra would tear Melmetal apart. <- This is to point out that talking about "potential" doesn't count. That's also why Noivern doesn't appear high up on people lists, despite having a good moveset and doing well against powerhouses.. being young and having plenty of room to grow.
Same with Incineroar. It had barely any good matches as a Litten/Torracat (Lurantis, Venusaur and Incineroar - not counting vs. Scizor, not saying it was weak, but it couldn't defend itself), but those shouldn't count as benchmarks as how strong it currently is. If they did count solely then Torterra's wins as Turtwig and Grotle should count as well and shouldn't be disqualified for it's losses in its final form (again, against three universally agreed upon powerhouses).
Personally, Snorlax still takes the 6th, maybe Lycanroc and Krookodile as close 7th and 8th.
1. Peakachu
2. Ash-Greninja
3. Charizard
4. BlazeNape
5. Sceptile
6. Snorlax
7. Krookodile (if you believe the conspiracy, it should've been caught during BW21/22 and Palpitoad wouldn't have happened at all).
8. Lycanroc (it's performances are plenty and substantial)
Then it gets tricky between the stuff like Incineroar, Melmetal, Torterra, Gliscor, Swellow, Glalie, Heracross and Bulbasaur. <- Descending generational order.