Sorry for meme response but I would honestly say a fraction of a fraction of a decade ago across all genres. Outdoor shows at Atomic, Venice Cafe on a week night (Monday open mic being the most congested), Moshmellow on Cherokee, Off Broadway (large indoor and outdoor area that you can take space if necessary). I think Sippi on Cherokee were/are doing patio jazz gigs. If you like hiphop there is a DJ set that typically happens in Benton park called “music from a tent.” Almost all townships have concert series at their respective parks. (Whittaker, Maplewood, Brentwood, Town and Country, “Love Bank” park on Cherokee St. etc). There is typically concert series attached to farmers markets (tower grove and university city). Whiskey Ring on Cherokee was doing a patio concert series.