I'll recommend my favorite 2 champs for each role. Hopefully you like at least one:
Top:
Kled, both in voice lines and lore, is a crazy yordle. The only time you should be playing safe on other champs is when you go ham on Kled. Fight, get dismounted, fight, get Skaarl back, win. He's an awesome rollercoaster of a champion. Ornn, on the other hand, is a very calm champion to play. He's extremely good right now, and he's not difficult to play. QEW auto is a surprisingly bursty combo, and his ultimate can instantly win fights.
Jungle:
Trundle is one of the premier junglers right now, but that doesn't mean he isn't super fun to play. His voice lines are goofy ("yOu'Re RuInInG mY gOoD mOoOoD!!") and his skirmishing ability is very good as well. His ultimate makes him surprisingly tanky, which is good when team fighting or split pushing, of which he can do both. Urgot DEFINITELY seems like a troll, but people overlook what he can do. His clear speed is CRAZY fast when you optimize his passive and W, he can skirmish early, he has a slow and displacement for ganks, and his ult allows you to kill low health enemies even if they're under tower.
Mid:
Xerath is the perfect champ for learning how to utilize skillshots, and he's a blast to play when you get the hang of things. He can poke from a mile away, his E gives time for a full combo, and his ultimate turns you into a living artillery cannon, which is so satisfying when cleaning up a fight. Corki, while not great right now due to being a late game champ, is fun in his feel, and brings a different ADC feel to mid lane. And believe me, if you manage to reach late game with Corki? He's an absolute monster that will shred through anything in his path.
Bot (ADC):
Xayah and Kalista both carry one of my favorite themes with any champions: using positioning to outplay opponents. With Xayah, keeping track of your feathers to land a crispy E root can make her have crazy burst damage that scares enemies out of lane. Kalista is the queen of kite. Hop hop hoppity hop around and dodge every skillshot they throw your way. At the end of it all, rip all of your spears from them and watch their health drop. Plus, they're both awesome at taking neutral objectives, as Xayah's feathers can do a lot of damage when stacked, and Kalista's E can do upwards of 3000 damage to objective when the spears starts adding up on the baron or dragon.
Bot (non ADC):
Lux has been the poster child burst mage for quite some time. Her poke in lane is good, her sunny disposition is fun to play with, and her QER combo does crazy damage and resets quickly on kills. Vladimir, on the other hand, is very strong right now. He's calming to play, and he doesn't get pushed out of lane easily. His vampiric theme makes him very fun, and his ultimate makes him a team fighting god.
Supports:
Rakan and Alistar share the theme of "Get in and stop what they're doing." Rakan has such consistent engage after level 6, and his E makes him hard to punish. Couple that with his uplifting personality and dialogue, he's incredibly fun to play. Alistar, however, likes to stay in the fight. While his dialogue could use an update, his combos and choosing when to use each ability makes Alistar a fun decision making champion. His ultimate also makes him extremely tanky, allowing for him to not get blown up after engaging.
I hope you like at least some of these champs. I love a lot of the characters, and I hope you find a champ you love too. Good luck!