I also add Bonfire Night but usually celebrate it at home and invite sims over if I want a crowd. If you set up all the fireworks close together or buy the festival battery boxes from debug then you can set them all off by lighting one. Sometimes I'll replace Harvestfest with this, other times I work around it.
Spooky Day (Halloween) is another regular add . I throw a Spooky Party sometimes too. Make sure to invite any known vampires or ghosts or other creepy sims to the party.
We don't have Independence Day/4th of July in the UK, so I add a Summerfest or PRIDE (depends on currently played household).
I add Springfest to cover Easter, spring cleaning and starting a kitchen garden (if sims don't already have one).
The "Vacation/Travel to Lot" tradition is a good alternative if you want to do "Attend Ceremony" but want it to be active. You can "Appreciate Objects" to contemplate a statue/idol of some kind, watch perfomances if you have the "Art & Music Spirit" tradition (great for setting up summer Music Festivals) and depending on the venue type you choose to visit NPC will do appropriate things and appear to be joining in with the celebration too.
I really wish the calendar was per household so I could set simified but culturally appropriate holidays for each and not have to set them up every weekly rotation. That way I could set my LGBT sims to always celebrate Pride, my Asian/South Asian sims could have/attend the Festival of Light, American sims could have Thanksgiving while British sims (Britechester) could celebrate Bonfire Night etc.