I think the most important aspect as black is trying to get the opponent into your territory. So if e4 happens, the Caro-Kann would be a somewhat easy way to deal with that. You also could go e5 and learn some tricky lines for the various openings, f.e. the scotch Steinitz Variation or the Traxler, because many people will not be familiar with it. For d4, you could go d5 and against c4 maybe play a sideline of the queens Gambit, f.e. the Albin Countergambit and against the London a quick c5 followed by nc6 and qb6. Alternatively, going for a Indian defense or a Grunfeld also works if you study those openings enough.
What can be my solid /best opening as black being a U1000?
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Just defend 1 e4 e5 and 1 d4 d5. Those are the most natural and objectively strongest defences.
Florian_luxi wrote:
I think the most important aspect as black is trying to get the opponent into your territory. So if e4 happens, the Caro-Kann would be a somewhat easy way to deal with that. You also could go e5 and learn some tricky lines for the various openings, f.e. the scotch Steinitz Variation or the Traxler, because many people will not be familiar with it. For d4, you could go d5 and against c4 maybe play a sideline of the queens Gambit, f.e. the Albin Countergambit and against the London a quick c5 followed by nc6 and qb6. Alternatively, going for a Indian defense or a Grunfeld also works if you study those openings enough.
Thank you for your ton of suggestions. I will study them with black and try them out 
Thanks for your help ✌️✌️👌
For u 1000 I don't think so that so many gambits are really required eg. Traxler , albins gambit etc. learning so many gambits could really confuse yourself not your opponents . During my way from 600 - 900 traxlers gambit was working fine but not for above 1000 and also it's very risky type as it contains so many lines to remember . I'm currently 1400 and I just know kings gambit i.e aggressive type , which I most oftenly play as white and the only thing you need to do is to perfectly master that one gambit or two which you want as per your choice and type . And about black I don't really use any gambit I just play along like developing knights and bishops.
Guys , I have been trying to hit the 1000 elo milestone for a year, in rapid chess and I have started to study openings , well for white the vienna is going decent for me but I still don't have any idea what can be a good opening for me as black . Can you guys suggest some ideas as black to help reach 1000 elo?