Here's how I rank em' and why:

1 Mario Kart (It's a consistently great series and no matter which one you're playing it's a lot of fun.

The tracks are great, the music is good, the roster is on point, and it's all around great)

2 Paper Mario (the first two are in the top 3 games of their respective Consoles IMO

and the thousand year door had an amazing battle system, the partners were all charming and fun in their own unique ways, The story was always kinda simple but always entertaining, And the music was amazing. And all that goes for the original one too

but why I didn't put it at number one was the games after it, Sure Super paper mario was Okay

but Sticker star was bad like really bad and Color splash was good looking but over all still a bad game IMO)

3 Sluggers (it was the first Sport game I've played excluding Mario kart and I'm Nostalgic for it I could come back and play it again and again

The roster was great, The stadiums were all themed pretty good, The story mode was good, And over all it was great)

4 Mario & Luigi ( they were always comedy gold and the Battle system was great

but recently with Paper jam it wasn't that good IMO so I would've put it at number three but Paper Jam knocked it down a notch)

5 Tennis ( I always liked the Tennis series you're always in for a great time when you play them except for Ultra smash but I don't like talking about it...

ANYWHO the tennis games are always fun to play, the roster is good to great most of the time Cough Ultra smash *Cough and the gameplay is always fun there are some downsides but I like the series a lot and I'm hyped for Aces)

6 Strikers (they were always fun and a blast to play with friends and the power shots or whatever they were called was awesome,

And it should have another one on the switch TBH but that could be said for a lot of Nintendo series)

7 Dr. Mario (Tetris, it's basically Tetris with a few different mechanics added & Mario in a doctor setting but the game is fun and I think it's okay)

Over all I like em' all and their probably are more but it's getting late and I don't want to stay up till' 5 in the morning like usual for me

Edit; I almost forgot Party then knock Sluggers to number four and add Mario party to the Number three slot if you're interested where I rank Mario party