xca
All data is saved in an encrypted, portable database, and can be exported in various standard formats. XCA is also available for MacOS X and Windows systems.
For a good workflow, certificate templates can be defined to make the creation of new certificates an easy task.
Latest reviews
2
XCA 1.4.1 (Mint 19.x) - Briliant. Ideal if you want an easy way to handle certficates. DB file can be placed on file server for easy access, backup etc. XCA 2.x (Mint 20.x) changed to using SQLlite which means it either needs a dedicated database backend or will only run on a local filesystem. If you use a central fileserver (eg CIFS or NFS shares) it will corrupt the database on opening and refuse all updates. At least it makes a backup before the upgrade. Effectively this kills the whole point of the it, which is a real shame. The 1.4.1 version seems OK on Mint 20.3 so you can download from the repo and install manually - just don't allow updates.
