SWTOR put actual extra *toolbars* behind the paywall. It is nigh unplayable without subscription. ESO, which I like, is also practically playable only in extra casual mode without ESO Gold membership (i.e. subscription).
Locked behind subscription and/or micratransactions in ESO (some come with subscription, some with gold, some with either):
* Some skill lines
* Many dungeons
* Expansion features (actual expansions are purchased separately, but many launch starter things are behind shop / subscription)
* Materials bank (all crafting materials are in your bags unless you get subscription)
* Most mounts / pets
* Thieves & Assassin's guild features
* Alt catchup mechanics (skyshard collections for alts)