After beating Inter Milan Barcelona qualified through out stage of the Champions League has reached its end, and we know what teams have qualified for the Round of 16. Thus, before the draw next Monday, Ernesto Valverde's side know their possible rivals in the next round.

They are Tottenham, Napoli, Lyon,
Chelsea and Atalanta, who have qualified in second place in their respective groups.
The other second placed teams were Borussia Dortmund, who Barça can't play having already faced them in the group stage, Real Madrid and Atlético Madrid, who can't meet Barça in this round because they play in the same domestic league.

So, the rival will be known next Monday, December 16, in a draw that will be held in Nyon (Switzerland). It should be remembered that Barça will play the return leg at the Camp Nou after winning Group F. The Round of 16 first legs will be played on February 18, 19, 25 and 26, and the return legs on March 10, 11, 17 and 18. All matches will be played at 9.00pm CET.

Source: http://www.kelvingolden.com/2019/12/barcelona-possible-rivals-for-champions.html?m=1