On the arch, from left to right: "Rainbow Kuriboh", "Kuriboh", "Kuribon", "Winged Kuriboh" and "Kurivolt"; center: "Kuriphoton".
"Kuri" (クリ Kuri) is a series of monsters used throughout Yu-Gi-Oh!, Yu-Gi-Oh! GX, Yu-Gi-Oh! 5D's and Yu-Gi-Oh! ZEXAL. Yusei Fudo is the only main protagonist who doesn't have a card from this series in his Deck. Instead, the protagonist-used "Kuri" in Yu-Gi-Oh! 5D's belongs to Luna.
In the anime, "Kuri" monsters are notable for being the Spirit partners of the main characters. A few episodes point out that "Kuri" monsters have special connections to the main characters who own various versions of this card.
In Yu-Gi-Oh! Duel Monsters, Yugi Muto started with "Kuriboh" and later added the other four "Kuriboh brothers" to his Deck during the Waking the Dragons arc. His Kuribohs focused on using "Kuribandit" as a Draw Engine and swarming the field with the effect of "Kuribabylon". He can discard his Kuriboh to reduce Battle damage that he would take from his opponent to 0 as well as use "Multiply" to protect him from battle.
In Yu-Gi-Oh! GX, Jaden Yuki's Deck includes a "Winged Kuriboh" that he received from Yugi. His Kuriboh strategy focuses on Summoning "Winged Kuriboh LV10" with "Transcendent Wings" and Tributing it to wipe out the opponent's Attack Position monsters and inflict damage. His manga counterpart also has "Winged Kuriboh LV9", which restricts the use of Spell Cards. When his "Winged Kuriboh" is destroyed, all Battle Damage he takes that turn becomes 0.
In Yu-Gi-Oh! 5D's, Kuribohs are used by Luna, a supporting protagonist, instead of Yusei Fudo, the main protagonist. Luna's only known Kuriboh card is her Spirit Partner: "Kuribon". Her strategy focused on turning the Life Point gaining effect of "Kuribon" against her opponent with cards like "Oberon's Prank" and returning "Kuribon" to her hand to reduce Battle Damage to 0.
In Yu-Gi-Oh! ZEXAL, Yuma Tsukumo has "Kurivolt" in his Deck. Its effect detaches Xyz Materials from any Xyz Monster on the field and produces an equal number of Kurivolt Tokens. It is currently the only normal Kuriboh that does not make Battle Damage 0. Yuma was so far the only protagonist that had used a "Kuriboh" card that did not appear to have a spiritual partnership with it, but during his time in Astral World, Yuma obtains "Rainbow Kuriboh", which was his father's card, and quickly forms a bond with it. Kite Tenjo also has a Kuriboh named Kuriphoton.
"Kuri" monsters are generally defensive in nature, and on their own, they tend to prevent Battle Damage from occurring to the user. However, some of their support cards allow them to rapidly turn the tables upon the opponent, such as the powerful "Winged Kuriboh LV10" and "Detonate". The "Kuribohs" all have 200 DEF, so "Flamvell Poun" would be perfect for searching your Deck for them. So far, all non-monster support cards for Kuribohs are Quick-Play Spell Cards allowing them to function quickly in a themed Deck.
Skill Drain Kuriboh
A Skill Drain Kuriboh Deck is based on "Kuriboh", "Winged Kuriboh" and similar cards that activate in the Graveyard. Since many of the cards has effects that sends them to the Graveyard and that they are LIGHT-Fairy or DARK-Fiend, "Chaos Sorcerer" and "Sky Scourges" could be useful.