I have a lot of things that I like, but XX is/are my favourite.
There are lots of things I like, but I like XX the best.
この場合、but を使って大丈夫ですよ!
−I have a lot of things that I like, but XX is/are my favourite.
「好きなものがたくさんあるが、XXが私のお気に入りです」
ーThere are lots of things I like, but I like XX the best.
「好きなものがたくさんあるが、XXが一番好きです」
ご参考まで!