Since its inception in 1992-93, the UEFA Champions League has been graced by nearly 150 different clubs from over 30 different national associations.
A total of 33 teams from 14 different UEFA associations have made at least 10 appearances in the Champions League over the years. This includes the 2021-22 campaign. 13 different teams have won the competition in the Champions League era. Unsurprisingly, most of these teams have been competition regulars.
On that note, here's a look at the five teams with the most UEFA Champions League campaigns (including the ongoing 2021-22 campaign):
#5 Porto - 25 (2003-04 Champions League winners)
Portuguese giants Porto have been Champions League regulars since the competition's inception almost three decades ago.
Sergio Conceicao's men are one of only seven teams to have appeared in at least 20 editions of the Champions League. They are one of 13 teams to have won the competition in its present avatar. Porto won the Champions League in 2003-04, led by their legendary manager Jose Mourinho.
They are perched in a tough group containing fellow competition winners Liverpool and AC Milan, and two-time finalists Atletico Madrid this season.
Porto are currently second in their group, ahead of their trip to group winners Liverpool. They will meet Atletico Madrid at home in their last group game, which could be a straight shootout for second place in the group.
#4 Manchester United - 25 (three-time Champions League winners)
Manchester United are one of seven teams to have won multiple UEFA Champions League titles.
The Premier League giants have been regulars in the competition. But they have alternated between the Champions League and Europa League in recent seasons. Since winning their last Champions League title in 2008, United have lost two finals (2009, 2011), both to Barcelona.
This season, United have struggled massively in the Premier League. But they have surprisingly fared well in the Champions League, thanks to Cristiano Ronaldo scoring in all five games this season.
His latest strike in the 2-0 win at Villarreal confirmed United's place in this season's Round of 16. It remains to be seen how far United will go in the Champions League this season, considering their overreliance on Ronaldo.