Anime features quite a number of creatures that can be summoned to be companions/fighters. In a sense, Shen-Long of DB/DBZ would qualify, but that's sort of cheating as he's not really summoned as either companion or fighter, but as a MacGuffin. I'm not even going to link to Pikachu, as there are something like (literally) a million pictures of him to choose from (and some of them highly disturbing. The goggles, they do NOTHING!), but I've always had a fondness for the little electric rodent. Naga the "White Serpent" from Slayers, scarily annoying though she was, was able to summon jellyfish; this of course has a certain resonance for me. Akazukin no Cha-Cha often would summon numbers of creatures (sometimes not exactly what she wanted).
But I cannot help but choose the summons that can also be a Soviet summon.
("What's a Soviet summon?")
"In American and Japanese fantasy, a mage can summon a familiar. In Soviet Union fantasy, FAMILIAR SUMMON YOU!"
And thus I can vote only for
Yes. Learn the Jutsu to summon the Toads, and sometimes they summon you. And train you to be the biggest badass in the world.
And these toads kick ass in MANY ways -- up to and including super-ninja skills AT THE SIZE OF GODZILLA.
Day 1 - Very first anime:Saint Seiya
Day 2 - Favourite TV series: : The Vision of Escaflowne
Day 3 - Your anime crush: Belldandy, from Ah! Megamisama/Ah/Oh My Goddess! and Shun from Saint Seiya
Day 4 - Favourite Film: Tonari no Totoro/ My Neighbor Totoro
Day 5 - Anime character you feel you are most like (or wish you were): Shikamaru from Naruto Shippuden
Day 6 - Most annoying anime character: Mihoshi, Tenchi Muyo!
Day 7 - Character you’d most like to slap: Sasuke, Naruto Shippuden
Day 8 - Most epic scene ever: End battle of YuuYuu Hakusho: The Poltergeist Report Movie
Day 9 - Saddest anime scene: Belldandy erasing herself from Keiichi's life in Ah! Megamisama/Ah/Oh My Goddess!
Day 10 - Favorite slice of life anime: Koko wa Greenwood
Day 11 - Favorite mech series: Giant Robo: The Day The Earth Stood Still
Day 12 - Best instalment of a franchise you don’t like: Nihao My Concubine
Day 13 - Worst instalment of a franchise you do like. Dragonball GT
Day 14 - Current (or most recent) anime wallpaper: Picture of Son Goku with Shen-Long done by my wife Kathleen
Day 15 - A reality check for a genre you like : Power-warrior anime and internal sanity/consistency!
Day 16 - An anime classic that simply doesn’t work for you: Neon Genesis Evanjellydonut... er, Televangelist...er, Evangelion
Day 17 - Best Background Music: Giant Robo: The Day The Earth Stood Still
Day 18 - Best Five-team: Yoroiden Samurai Troopers/Ronin Warriors (no link, too expensive)
Day 19 - Change you’d like to make to any one anime: Specific Change: Eliminate one nasty action from the history of Juraia-sama in Naruto/Naruto Shippuden. General Change: Eliminate the Saiyajin focus and expand capabilities and screen time for all major characters in Dragonball Z.
Day 20 - Most ambiguous anime character: Selected Maraich and Patalliro, from Patalliro!
Day 21 – Favourite OAV Series : Except for two I've already mentioned, Bastard!!
Day 22 - Animation studio you'd most like to slap: Gainax, for Neon Genesis Evangelion
Day 23 - Anime you think had the best, or most intriguing art: The Five Star Stories
Day 24 - Favorite anime hero or heroine: Uzumaki Naruto from Naruto Shippuden
Day 25 - Best anime villain: Orochimaru, Naruto Shippuden
Day 26 - Your favorite harem anime: Ah! Megamisama/Ah/Oh My Goddess!
Day 27 - Favorite anime opening theme song: Pegasus Fantasy, Saint Seiya
Day 28 - Favorite anime companion/summoned creature: Narutoads!
Day 29 - Best Anime Music Video
Day 30 - Favorite anime ending theme