The Paladin being the strongest class is simply my opinion. I'm sure not everybody would agree although I know a lot of people do. Take a close look at the class and add what you get. Pretty much all of the Oaths are strong in one way or another too. Pairing the Pally with any other Charisma based character like Bard, Warlock, and Sorcerer would be extremely strong. Pally/Warlock gets you recharging smites on short rests too.
I thought of another fun one. Oathbreaker Pally 20/Necromancer Wizard 20. You could make an overpowered undead army. The synergy is perfect. Throw in some Death Cleric too for even more fun.
You could ask your DM if you can take the same class to 20 twice. Like take Champion Fighter to 20, and then take Battlelmaster Fighter to 20 again and treat them like 2 separate classes instead of Fighter 40. You'd get 8 attacks, 3 fighting styles and 4 action surges.
Moon Druid 20/Monk 20 would be fun as well as Moon Druid 20/Barbarian 20 so you can rage in animal form but ultimately, Druids don't multiclass as well as most classes since your physical stats change as you shift from animal to animal.
I thought of another fun one. Oathbreaker Pally 20/Necromancer Wizard 20. You could make an overpowered undead army. The synergy is perfect. Throw in some Death Cleric too for even more fun.
You could ask your DM if you can take the same class to 20 twice. Like take Champion Fighter to 20, and then take Battlelmaster Fighter to 20 again and treat them like 2 separate classes instead of Fighter 40. You'd get 8 attacks, 3 fighting styles and 4 action surges.
Moon Druid 20/Monk 20 would be fun as well as Moon Druid 20/Barbarian 20 so you can rage in animal form but ultimately, Druids don't multiclass as well as most classes since your physical stats change as you shift from animal to animal.