Rerolls, Inspiration, Etc for Dungeons and Dragons

For the past 9 years I have used several different systems for allowing players rerolls. Below are the different ones I have tried during Dungeons and Dragons games.

Version I

In the first system I used PCs started with 6 rerolls at level 1 and gained 1 new reroll every time they went up a level. This made rerolls rare and precious - and sometimes forgotten about. Added to this a PC could also do something to earn a bonus reroll which could be cashed in later (similar to Inspiration in 5th Edition).

"Oh yeah. I forgot we had rerolls."

Version II

The next system I used was based on Charisma, which made Charisma a more important stat. PCs got 1 reroll per session, plus a bonus reroll per session for having higher Charisma of 12, 14, 16, 18. A PC with an 18 Charisma gets 5 rerolls per session. This made rerolls quite common. (As a bonus players also got Double Rerolls whenever our Friday game was on Friday the 13th.)

"Bah, I will just use a reroll. I have 4 of them!"

Version II B

This adaptation came later in which rerolls could also be burned to add +4 to a d20 dice roll or +/- 20% to a percentile dice roll.

"Hmm. Barely missed. Screw it. I will burn a reroll so I hit the demon."

Version III

This is my current system for my Friday game. 1 reroll per session. No burning rerolls. This makes rerolls more rare, but players are less likely to forget that they have them now because they are so accustomed to having them.

Version IV

(This one is still in the design process.) My goal is to make a Deck of Reroll cards. Each reroll card can be cashed in for different things.

Reroll Saving Throw
Reroll Skill check
Reroll Ability check
Reroll Attack
Reroll Damage
Reroll Anything (more rare)

In a 52 card deck there would be 10 of each of 5 basic reroll cards and only 2 Reroll Anything cards, making them almost as rare as jokers.

Players would get to draw 1 card per session at the start of the game and could earn bonus cards during gameplay (similar to Inspiration).

Version IV B

My last idea is similar to IV, but using a regular deck of cards. Each suit has a different effect. Instead of rerolls the cards provide a bonus.

Spades - bonus to damage.
Hearts - bonus to saving throw.
Diamonds - bonus to skill or ability check.
Clubs - bonus to attack roll.

Ace to 10 - bonus of 1 to 10.
Jacks, Queens or Kings - gain Advantage on the roll. Reroll and take the better of the two.
Joker - Can be used to reroll anything twice. Choose the best of the 3 (aka Super Advantage).

Unlike Version IV in this version they keep the card from session to session and can end up getting a maximum of 5 of them. Some of them (like Aces and 2s) would like be used fairly quickly and not saved, but Jokers, 9s, 10s and face cards would be useful to save for boss fights and rainy days.

Thoughts on these? I know not everyone is into Rerolls or Inspiration. Leave your comments below.