NGC 2362 - nicely shows the effects of averted vision
NGC 3532 - so many, so even (others in the Carina area, NGC 3293 & 3114)
NGC 2516
M7
M41 is a sentimental favourite - first thing I found by myself way back when I was a kid with a telescope and a star chart.
My daughters like open clusters as they make shapes out of them, for example penguins, mice and the like - not sure I can see them though, perhaps my imagination gene is not very strong.
Favourite NGC 6231 in Scorpius
then NGC6255 - jewel box
Eta Carina area fantastic - forget the number but one of those clusters wont fit into my widest EP
Ah! NGC 3532 The Pincushion Cluster. Been looking at it tonight. Many bright stars almost seem evenly spaced, just lovely. Try and tear yourself away from Eta Car for a few seconds to check out "one of the heavens true stellar spectacles" to quote O'Meara.
Some of my favourites are:
M11 (Wild Duck Cluster) in Scutum.
M46 in Puppis with the chance alignment planetary nebula NGC 2438.
NGC 3293 (Gem Cluster) in Carina- compact, rich.
NGC 3766 (Pearl Cluster) in Centaurus.
NGC 4755 (Jewel Box) in Crux. A popular target.
NGC 6231 in Scorpius- bright and with nearby trio which includes zeta2,1.