In EE2 I made an event calendar with Low Events. That fieldtype was super useful. But now EE5 comes with a "Date" fieldtype that might just be fine, by the looks of it. Would this be a good practice in making an event calendar, or is there an addon out there that is really useful for an event calendar?
If you are developing the website in EE5 and you've very easy functionality then you should go with Calendar Tag which is built in tag of EE.
And if you are developing the website in EE2 or you have some complex functionality in EE5 with Calendar then you should go for Solspace Calendar.
Both are very useful but all things is depends on your requirement.
I'm ending up going with Low Events (https://gotolow.com/addons/low-events) again. I used it back in EE2. EE5, while having a nice "Date" fieldtype (for Start and End values of an event), doesn't have good date filtering based on that like it does with Entry Date in the Entries or Calendar tag parameters.
I have no doubt Solspace Calendar is great, like the rest of their software. But going with Low Events to make porting easy.