The detachment from characters you have grown fond of over the course of 12 years is not easy: the fans of The Big Bang Theory they can testify, for example, how strong the lack of Sheldon, Penny, Leonard, Raj, Howard, Bernadette and Amy is after the conclusion of the famous show.
The careers of our heroes, however, certainly do not stop there: in the future we will certainly have the opportunity to review Jim Parsons and co. in other roles (Parsons himself will participate with Mayim Bialik in Call Me Kat, while Kunal Nayyavi will be part of the cast of Criminal). Of some of the protagonists of The Big Bang Theory, however, we have not yet heard of outside the show: Simon Helberg, eg.
Howard Wolowitz’s actor obviously appeared on several occasions outside Sheldon and Leonard’s apartment: we remember him for example in films such as A Serious Man (2009) or in the more recent Florence, dated 2016. On TV his last appearance not related to the show that made him famous is instead the one in an episode of Drunk History, in 2013.
As for his future, the only certainty is Annette, a film due out (barring complications) in 2021 which will see him act alongside Adam Driver and Marion Cotillard. Looking back, meanwhile, a fan recently uncovered a mistake in an old episode of The Big Bang Theory.