This list is specifically for second chances/age regression in fantasy, historical or VRMMO settings. 
- Not transmigration stories (see: https://www.novelupdates.com/viewlist/16246/)
- Not time loop stories (see: https://www.novelupdates.com/viewlist/10681/)
- Not second chances in modern society (see:  https://www.novelupdates.com/viewlist/10745/)... more>>

I'll start with a big recommendation for:
1. Metaworld chronicles - wonderful series with well developed characters, magic, monsters and dragons, all set to a really well explored alternate modern Earth fuelled by magi-tech. It's the best in the genre and you should try it out!
2. Selena's Reign - only around 20 chapters out so far, but they're really well done. Beautiful descriptions (though sometimes a bit verbose) and the best depictions of a late 18th century setting that I've seen in an online fantasy. Read this for the magical second chance messiah in a gritty, Louis XIV->Napoleon type time frame world.
3. The Calamity of a Reborn Witch - more of a shoujo take on things, it's filled with political plots and conspiracies of a cinderella type heroine in a rather dark fantasy world
4. Forgotten Conqueror (this was on hiatus for a long time but restarted on the author's site) <<less