The Deep Gnome (also known as the Svirfneblin) was republished in Monsters of the Multiverse, and they got some major changes. Their Darkvision was reduced to 60 feet, Stone Camouflage was replaced with Svrifneblin Camouflage, which works anyway but only PB/long rest, and WotC added some innate spellcasting similar to the Svirfneblin Magic feat.
The new Deep Gnome is now useful outside of rocky terrain (a challenge for the previous version). They’ll excel with stealthy builds, but will likely struggle to be useful if you want to stomp around in plate armor.
