Last month, nurse Namco Bandai filed three Tales of trademarks for what seems to be the next Tales of game: Tales of Zestoria, Tales of Creales and Tales of Catastora. This month, Namco Bandai filed two new additional trademarks which seem to be in line with Zestoria: Tales of Zestiria and Tales of Zestias.
Casual reminder that this does not exactly set in stone that the next Tales game will be one of these titles, but they are definitely leaning toward these. Whatever the next Tales game will be, it seems that they're leaning toward "TOZ."
Thanks to @Flamfas for the heads-up.