The Z on ETHZ is important, ETH on its own is just (loosely) "university", the Z makes it the Zürich one ;D. There is exactly one other: EPFL in Lausanne. (And you can technically call them EPFZ and ETHL if you really want to confuse people.)
(EPF [École Polytechnique Fédérale] is just the French version of German ETH [Eidgenössische Technische Hochschule]. Funnily enough both have pretty good international reputations, but due to the primary regional language being different are rarely recognized to be the same type of Swiss education entity.)