It's 99% certain that Malbung (my bard /hexblade) will take blade and not tome as his boon, so that makes him pretty short on rituals too ... I don't know if *any* of his spells are rituals....
...So I checked, and he has 2 - Leomund's tiny hut, unseen servant as spells (not at my books, so I don't even know if warlocks automatically can use rituals or not). He *does* have the invocation that gives him detect magic at will, but that might get traded out in the future.
Lastly maybe the Mystic (played by [MENTION=6855204]tglassy[/MENTION] ) has rituals? I have no idea about that class and such effects.