Oh there is many. I don’t like reunions, especially since all our favorites are becoming old by now.
Nightwish with classic line up - see Nightwish thread.
Stratovarius with classic line up - Stratovarius is really on fire nowadays. The new album is their best in God knows how long. They don’t need no reunite in my opinion, but I’m sure they get offers all the time for Helloween style reunion. Timo Tolkki is still very fragile, still has lots of problems, and don’t want to tour for weeks on a bus, so I don’t think he will be back other than the occational performance. I think Jani Liimatainen will join them if Mathias quit one day. Jari and Jörg should be no problem being back in the band.
Sonata arctica with Jani Liimatainen and Marko Paasikoski - It could happend one time, but not until they are done releasing the new album and the upcoming world tour.
Battle beast with Anton Kabanen - Probably in 10 years time, or earlier if one of the bands fold first.
Guns’ n roses with Izzy and Steven - I’m very happy for the last seven years. All they need to do now is record a new album with new original songs. It will never be as popular as back in the 87-93 era. So if Axl feels he need more cash, he has to reunite with Izzy and Steven. Guess both are not up touring for years though.
Immortal with Abbath and Horgh - Abbath will play only Immortal songs next year. The writing on the wall is there. They need to lay of their egos all of them, stop suing each other, and just show up in a rehersal room and cranck out some tunes
Opeth with Peter Lindström back - probably not, but who knows?
Marillion with Fish - It will never happen full time, but maybe some special gigs before it’s too late?
Edguy - no activity since 2017. Avantasia got bigger and more profitable. In 2027, I guess they will return after getting an offer they can’t refuse.
Skid row with Sebastian Bach - this is one thing I actually hope it will happen some day. But someone must pay them a shitload of money for it to happen.
System of a down - Will they ever release a new album and do a world tour? I think not
Venom with classic lineup - Maybe if they get paid alot, they will do some one off with Mantas and Abbaddon?
Gamma ray with Kai Hansen back on vocals - this will probably not happen, especially as he is back full time in Helloween, but maybe Wacken will pay Kai & co tons of money for a one off gig doing either Land of the free or Somewhere out in space one day?
Blind guardian with Thomen Stauch - No, at least not a fulltime gig.
Kamelot with Roy Khan - I can see this happen in a few years. If Khan can handle heavy touring.
Rhapsody of fire with classic lineup - It will probably never happen, at least not with Luca Turilli. He seems done with metal music. But maybe one or two other members could come back.
Sigur Ròs - They only miss Orri now. I hope he comes back soon, their last album really miss his drumming.
Simon & Garfunkel - Guess it’s too late. They are both very old now, and have reunited countless times. They should enjoy their retirement with their grandkids instead.
Oasis - Probably not
Savatage - They are on their way back. Hope they can keep it up a while, but Jon’s comments implies they are not in for the long run, just closing the circle.
Sepultura with classic line up - not too unrealistic, but someone is very stubborn there. Sepultura do fine with their current line up thought
Judas priest with KK Downing - it will never happen. The guys have just a few years left, and no one seems to be talking at all. The same can be said about Udo, Peter Baltes and Accept, Deep purple and Ritchie Blackmore, Yngwie Malmsteen with a singer
Faith no more, Queensryche and Rage against the machine (classic lineups) - Give them ten years when the members are broke, and they will do one final tour.
Mötley crue and Kiss should have quit in the early 2000’s when they actually reunited and did very well. Slayer and Black sabbath will probably never play together either.