Matches with Leo
Another Fire sign is good for a Leo simply because their energy levels are similar. Any sign that is sextile (Gemini, for instance) or trine (Aries) would be fine, too — though Leo has little patience for Aries who aren't spiritually evolved. True, he may win her for a while, but then what? He can be too headstrong. Aries is a lot like Sagittarius with Leo — lots of fire, but not the same temperament. Sagittarius can be a bit too wise and quiet (or even too superficial or stubborn) for Leo; Aries can be too demanding and controlling.
The polarity between Leo and Aquarius, its polar opposite sign, may elevate a Leo's consciousness to where it succeeds best — to the wider world beyond himself, if the Leo has some Air signs in his chart. Capricorn can be an interesting match and Scorpio seems like a go until Leo realizes that she may not like the way he may raise their children. But they're surely a good match in bed.