The eighteenth card is One for One, a card that lets you discard a monster to special summon a level one monster from your deck or hand. There are various cards that this can combo well with, the Black and White Stones of Legend, for example, in fact a number of archetypes have level one support that need to be on the field for a time. There are also cards like Copycat and Flamvell Guard that can be summoned with this and can have a good amount of attack and defense. You can also use this card to help set up for things like Law of the Normal and Triangle Power. It is a summon that can search the deck for you, and can be useful in some of the archetypes and level one monsters have some support of their own as well so a pretty good card.
Yu-Gi-Oh Advent Calendar 2019 17 Kuribon
The seventeenth card is Kuribon, a Kuriboh that showed up during 5D’s. For Kuribons effect it has to be the target of battle, you can make the result of the battle be your opponent gains their monsters Atk points as life and Kuribon returns to the hand. This means that as long as you don’t mind using up your summon and giving your opponent Life Points you can block one attack per turn. There is another card with a similar effect called Scrap-Iron Scarecrow that stops an attack per turn as a continuous trap. Ordeal of a Traveler and Gravekeeper’s Servant can be used with these to great effect on how many attacks can actually go through. Another option would be having a Bad Reaction to Simochi on the field to force your opponent to take damage instead of gaining it when attacking into Kuribon. Since none of those cards need your normal summon you can use Kuribon to stall for time to get them as well. It’s a pretty good stalling card on its own so it’s a great addition for decks if they can afford not to worry about how much life their opponent gets.
Yu-Gi-Oh Advent Calendar 2019 16 Kuriphoton
The sixteenth card is a Kuriboh from ZEXAL, Kuriphoton. This one is a costly shield, discarding it and 2000 LP to stop any other damage from happening for the turn. It can be regained if you discard another photon monster, so if you run those and have a way to make back the life points this could actually be a great card to use, but without healing cards you have at most three turns of stalling with this card, and you won’t have much life left when it ends. Of course if your opponent has more than 2000 atk coming at you then using this is obviously a great idea. Honestly despite the LP cost it probably is a good card to run. I’m pretty sure you can gain life fast enough to do it indefinitely, though I’m not sure about doing that and having the photon monsters to get Kuriphoton back from the graveyard.
Yu-Gi-Oh Advent Calendar 2019 15 Detonate
The fifteenth card is one I’ve been waiting to see since Multiply appeared, Detonate. Detonate lets you destroy all your Kuriboh and Kuriboh tokens to destroy cards your opponent controls up to however many Kuribohs you destroyed. It works great with Multiply or if you used Kuribohrn to get Kuribohs back. It does only work with Kuriboh though, so if you don’t run that version of Kuriboh you won’t be using this card. It still is good if you use it, it can destroy monsters, spells, and traps which is a versatility that most card destroying effects don’t seem to have.
Yu-Gi-Oh Advent Calendar 2019 14 Kuribohrn
The fourteenth card is Kuribohrn, which was made to support the other Kuribohs. This one can be discarded to revive one of your monsters that has just been destroyed by battle, but its main effect is that you can banish it from the graveyard to revive as many “Kuriboh” monsters that you have room for. That effect could be useful if you combine it with the Kuribohs that have effects on the field like Relinkuriboh and Winged Kuriboh LV9. It can also be good for getting fodder for any summoning that can use level 1 monsters. This is one of the cards that can help a good number of the other cards in this advent calendar which is neat.
Yu-Gi-Oh Advent Calendar 2019 13 Relinkuriboh
The thirteenth card, Relinkuriboh, is a Kuriboh that has yet to show up in the anime or manga of Yu-Gi-Oh. If you tribute it you get to draw a card, and it can banish itself from the graveyard to stop one of your monsters from being destroyed by battle. If you want to take advantage of Relinkuribohs first effect you need a way to tribute it, which could be for summoning a higher level monster or to use effects like with Cannon Soldier or Obelisk the Tormentor. Honestly as long as you can get the first effect off it’s probably worth using.
Yu-Gi-Oh Advent Calendar 2019 12 Sphere Kuriboh
The twelfth card is also a Kuriboh from Vrains. This one when you discard it in response to an attack forces the monster into defense mode, which can either stall for a bit or force the enemy into a place they can be destroyed. Its second ability lets it be banished from the grave to help in a ritual summoning. This can be moderately useful in any ritual summoning deck, especially when the ritual spell requires the exact level. It’s a good card if you have ritual monsters, and if you don’t want to use Multiply or Detonate then it should be better than the standard Kuriboh.
Yu-Gi-Oh Advent Calendar 2019 11 Linkuriboh
The eleventh card is Vrains Kuriboh. This one is a Link monster that needs a level 1 sacrifice to summon. It can be sacrificed to temporarily set an attacking monsters atk to 0, and it can be summoned from the graveyard just like if it was in the extra deck, though you can only summon it from the graveyard once a turn. As long as your deck includes level 1 monsters Linkuriboh can be added to the Extra Deck as a nice option to stall things.
Yu-Gi-Oh Advent Calendar 2019 10 Rainbow Kuriboh
The tenth card is another Kuriboh from Zexal, the Rainbow Kuriboh. It can be equipped to an opponents monster when they try to attack and stop them from attacking at all, and if you’re attacked directly and it’s in the grave you can special summon it and when it next leaves the field it gets banished. You can use those effects once per turn. The first effect is actually pretty good, and since it can be applied during your opponents battle phase you don’t have to worry about them sacrificing the monster for something else before a turn has passed. This Kuriboh actually has less atk and def than normal Kuribohs, having 100 of each. The second effect can shield for a hit and works from the grave but that’s about it. It might be useful but probably only if you are going for a Kuriboh deck or something that requires equip spells.
Yu-Gi-Oh Advent Calendar 2019 9 Kurivolt
The ninth card is ZEXALs Kuriboh, Kurivolt. This one is actually more about interactions with Xyz monsters than battle, being able to erase a material to summon another Kurivolt. It can’t be used in Synchro Summoning, but it could be useful in both Rank 1 Xyz monsters and with link summons. It seems like one of its main uses is to erase one of your opponents Xyz materials, and is definitely worth having if you’re up against someone that works with Xyz often.