Seeing more of TNA history from the time I stopped watching (2011 - 2015, without any spoilers), and I must say I love their match types and concepts. I find them much more exciting than WWEs match types minus Hell in a Cell and my personal favourite Elimination Chamber

and I have been missing out on a lot.
Feast or Fired concept is far more interesting than Money in the Bank, not only is there 4 Briefcases but 1 of them contains are Pink Slip meaning your fired (sometimes in Storyline, sometimes Legit). My only complaint is that the Feast or Fired match itself is horrible in comparison to Money in the Bank as the Feast or Fired matches are objects on poles matches :/
King of the Mountain can be an unpredictable match and is honestly one of my favourite things of TNA, they now have a Championship which is based off this match. However, the only flaw is how much Jeff Jarrett gets exposed in these matches which seem a little cheap as he is the founder of TNA.
Do I really need to explain Ultimate X matches

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Lethal Lockdown, to me feels like TNA's answers to WWE Survivor Series and WCW's War matches but it is rather interesting on how this works, and when all wrestlers are in, Items come in and the Cage roof is applied allowing for an all out wall.
Option C, I find is a good way to make Minor Guys get pushes, as this concept allows the Minor Champion (TNA X Division Champion) to vacate his Championship and go for the TNA World Heavyweight Championship at Destination X, not only does this push the minor guys but it also means that there is a guaranteed new X Division Champion which is usually exciting to see what happens.