Hello everyone. I felt the need to do this since unlike Runes, Relics get new additions once in a while, and it'd be a chore to update every single one of my analyses just to add said Relic to my list of options. Instead, I will analyse every respective Relic here and tell in which situations or on which kind of monster they'd be useful on so that you may experiment more freely and I may relieve myself of the need for updating my past analyses.
Before beginning, I must mention that some Relics are obviously weaker than others and some Relics are not useful at all. To more effectively show this, I will list the higher powered Relics before those inferior ones so that you can know the one below is weaker than the one above, but can sometimes be used as a substitute if you don't have access to the latter.
Staves primarily focus on Stamina control, but there are ones that deal damage or provide protection as well. This makes them an all-around good slot to have, since you can't go wrong with Stamina control.

Gakora's Staff: If the enemy has a team that focuses on Control effects to win, this Staff will prove to be very useful. It'll also potect your monsters from the enemy attacker's assaults and Torture effects.

Nadiel's Staff: This Staff requires you to use Stamina Drain, making it decent on monsters with the effect. It can also be used on attackers alongside Stamina Drainers to boost their damage output, plus the decreased Speed can help in the long run. However, it's not as impactful as the other Diamond Staves.

Cane of Atlantis: This Staff is excellent in any situation, given the abundance of Stamina Draining Relics. It's perfect for countering Relics like the Oblation Trap and Jasastur's Mask, or against monsters like Mephisto. It can be used to assist extra turn spammers or monsters with high Stamina costs like Talos or Cryotan as well.

Staff of Despair: This Staff does not drain as much Stamina as other Gold Relics that do the same, but this one has a catch: the enemy that loses Stamina from this loses it forever, meaning you can use it against monsters like Talos and General Thetys, and prevent them from using Talos is the Sun and Stamina Devourers, respectively. Other than this, the lost Stamina will cause enemies to recharge more frequently, which will prove to be crucial in battles that will take long. However, you'll need a monster with Freeze or Stun to use it.

Revenge Staff: This is a good Staff that is generally useful. It's especially good against monsters with extra turn moves since the Stamina Drain, combined with the move's Stamia cost, will probably require them to recharge.

Oblation Staff: This Staff is excellent on deniers that don't use Stamina Drain, as it will drain the Stamina along with the deny effect, which results in a 2 turn deny if the Staff is high leveled. Other than this, like the Revenge Staff, the Oblation Staff is a generally useful Relic.

Energizer Staff: Inferior Cane of Atlantis.

Drainer Staff: Inferior Oblation Staff with an added Life requirement.

Avenging Energy Staff: Inferior Revenge Staff that drains from a random enemy instead.

Charging Staff: If you have no higher rarity Staves, this can be useful on monsters with Stun.

Shaman Staff: Skip.

Spirits Staff: Skip.

Cold Staff: Skip.

Punisher Staff: A similar situation to the Charging Staff.