7.
Midna- Midna may seem reluctant at first, but she helps Link a great deal throughout his journey. Not only does she allow him to reach places he wouldn't be able to otherwise, but she can also change Link's form from human to wolf and vice-versa. To top it off, she can teleport to different areas of the map for your convenience. Or laziness.
6.
HK-47- From the KotOR series, HK-47 is a robot programmed to assassinate anyone you'd like him to. He is proficient in droid weaponry and blaster rifles, and can also do some repairing, disarming, and slicing of computer systems. He also knows secrets on how to defeat a jedi from his previous work, so overall, he is an enormous help to your jedi!
5.
Maya Fey- There is no way Phoenix Wright would have been able to solve multiple cases without the help of Maya. Not only does she use her spirit channeling to contact her dead sister, Phoenix's mentor, but she also ensures his trust in his clients and on occasion, finds evidence vital for cracking a case.
4. 
Pikmin- Captain Olimar wouldn't have survived if it weren't for these adorable sprouts. These guys killed off the monsters and sacrificed themselves to help Olimar get his ship in working order. You can't get much more of a companion than that. In large numbers, these plant-like creatures can carry large objects for long distances to the ship. Clearly more devoted than most any other accompaniment.
3. 
Helper- In Kirby Superstar [Ultra] you are given the ability to create a helper of any element or item you first mutate into. Not only are these helpers active in helping you defeat baddies, but they can heal you! For a price. Kirby has to kiss his helper, and they'll revive some of his health. I bet Yoshi can't do that. Then again, I never tried kissing him. Don't you go and do it, either.
2. 
Kazooie- Kazooie is Banjo's backbone... Literally. This bird stays in Banjo's backpack most of the time, but that doesn't mean she doesn't offer much aid. In fact, Kazooie is extremely useful. Banjo, being a bear, can't go up steep hills, attack from afar, or reach enemies when on a ledge. Kazooie offers all of these and more! Without her, Banjo wouldn't be able to get to many of the places his journey require him to venture through, and his poor honeycombs would go much quicker.
1. 
Pokemon- That's right. Pokemon. Not Yoshi. Not Luigi. Not even Epona, despite my passion for her. Pokemon do so much work that it sometimes seems like the pokemon trainer is the sidekick! Pokemon do all of the labor. They keep their trainers free from harm, use their special abilities to get to new areas, and are your best friend. Nothing beats a trusty pokemon.
An honorable mention goes out to Eric for helping me with this list.
