Ice Climbers, Zelda, and if im feeling like really working for my win Samus w/ or without armor.
Ice Climbers are just amazing they can really do alot of damage on the same level as bowser but arent so horribly slow. And if theirs items.... like fans you get each ice climber one and your pretty much guarenteed to take someone to 999 in a few seconds lol. Weak Final Smash but it does make the enemy do nothing but jumping so you can always get some nice hits in while there falling down back to the ground.
Zelda/Sheik just rapes, you got the wide selection of styles with them at your arsenal, Speed / Power in a few seconds. Final Smash is amazing as well.
Samus is simple and easy to learn. Always used them in every Super Smash, and there have been little to no changes with her. Final Smash reminds me of
Goku's Ka-me-ha-me-ha wave from DBZ so using it makes me happy. W/O armor samus gets so much more range in attacks and annoying stun moves. Not to mention spawning with 3 tossable objects that rape hard isnt bad either lol.
Honorable mention, Poke'mon Trainer. If he didnt change after you die or take so freaking long to switch to his other poke'mon he would be the absolute best character no questions about it.