@Jean Grey Why should Invel be so low? He was Zerefs right hand man and could create snowstorms in a large area. Plus his ice magic made Gray shiver and if Gray weren't in his emotional rage mode (plot) he would die against Invel's true ice Kamui spell. I don't see how Bloodman could be stronger? Or Wall. Dimaria and Brandish, yeah maybe both are stronger but only if their magical powers are stronger than Invel's. If not then he would beat them. I hope in the 100 years quest Brandish or someone else will tell the strength list about the S12. But I doubt it. xD
@Axiomus
Why not? Zeref would have infinite power. Of course he loses to Natsu. But that was only because of plot. Without that he could kill Natsu easily. Yeah, it's a fact that Natsu beats FH Zeref but examples like that I don't count in tier lists. Everyone knows that plot induced events are not countable. For me at least. It's just like Dragonball. 98% of the characters in this series can destroy planets. But every time when they fight each other only rocks are going to be destroyed. So without the demonstration that someone can wipe out a planet, it's a fact that these characters can't doing it? Or examples like One Piece many antagonists could kill the protagonist easily if they wanted. But again because of plot they were all beat.
But this is a little bit off topic. Sorry. Back to Zeref FH Mode. I think he could beat Acnologia, if he casts Neo Eclipse with this spell he could kill everyone in a few seconds. So how could Acnologia survive this? And even without this spell he could cast many other spells with his infinite power, just like Mavis said, infinite Etherions could beat Acnologia. Maybe he could survive this but he couldn't do anything against a endless spell. So I didn't know why not. Maybe you can explain why he is stronger than FH Zeref.
Yeah this was my fault, as I create the list I only had the image in head how Mard battles the Celestial King and the Celestial King is one of the strongest characters (now I realize that I forgot him in my list and Jellal too xD), but yeah the Dragon Eaters or some of them were stronger than Mard. But for me at least Mard is a powerful character he could be a low Spriggan tier. Because he was very powerful he only lost because of the devil slayer magic. I am sure even after the time skip between Tartaros and Alvarez he could beat many characters, in my opinion a low Spriggan too. Maybe Jacob or Neinhart or Ajeel too.
As for Azuma I put him above Neinhart because Neinhart's magic is too weak. Erza only lost because many of her former opponents were dead and because she was wounded due to the battle against Ajeel. And the three Spriggan that Neinhart summoned in the war, was a situation in this war. Who said that he could summon them whenever he wants? It's not so that Neinhart gots stronger because 3 of the Spriggan 12 dies. Neinhart had the power to do that previously too, but that doesn't mean he is stronger than Azuma, Bluenote or other old villains. Who knows whom he can summon in a battle. It's not a fact that he could summon characters every time just like he did in the war. Therefore, for me he is weaker than many others since it's a 50/50 chance for him depending on who is his opponent. In other words, what would he have done if Azuma, Kyoka and Ikaruga were alive? Erza would have beat him in a few seconds. And his own Historias? Yeah, in this time all of his comrades were alive so what would he do in such a case like this? Or in a case where someone like God Serena is alive? His magic is very risky. And without his Historias he isn't a strong opponent. A lot of characters could beat him. After the war...yeah he could summon his death comrades but could he do it every time? Because, it's cost him a lot of magic power and time(?) too. In this time he could be beaten. Maybe he could do something with his wind magic but no one knows how strong he is with it.
In the last point. You're right, I totally forgot about his DF mode. If it isn't a temporary power up he would be above both of them. But I wouldn't say that Kagura and Minerva are weaker than Warrod. Warrod is only a supporting mage with a lot of magical power, but that's all. And the other saints like Wolfheim or Hyberion are lower in my list because they didn't show anything that would put them above the others. But Jura is probably stronger than both, that's right.
@Benomaru
Thanks.
Maybe you're right. Acnologia is probably stronger. That's why I put him above Acnologia only because of hype higher than Acnologia. Ignia is very arrogant so yeah in the end he would be weaker than Acnologia, but who knows, maybe he is really stronger or at least equal. But I doubt it too. It's really a shame that the Alvarez arc was rushed and had so many hax abilities. Acnologias "magic dragonslayer magic" or whatever the name is, was in my opinion the most bullshit hax power in whole Fairy Tail and one of the top 10 in Mangas overall. I'm really happy that the 5 God Dragons had only their one element and I really want to see Selene and her(?) Moon Magic. I hope it's good
@Akaneko Kogetsu
Thanks. Your list is cool too.

It's really a shame that Juvia didn't show anything new since Tartaros or a good battle.

I hope that she will later fight a Diabolos member and wins with new power.