We have around 250 projects in JIRA, and the list of projects was becoming unmanageable when creating an issue, and in the issue navigator. I modified the templates so it groups them in to “my” projects, versus “other” projects:
By default we create projects with jira-users in the Users role, giving people Create Issue and Browse permission in the project. We do this firstly in the spirit of openness, and secondly to reduce the effort for project administrators… if we didn’t do this they’d need to manually add people in to the role when they wanted someone to look at or create an issue.
But the consequence was very long lists of projects by virtue of everyone being in jira-users. “My Projects” are any projects where the current user has an explicit role membership for by name, and any projects where they are in a group that is in a role, which is not jira-users or jira-administrators.
This is not a proper plugin, but feel free to download the source here. (Written and tested against 3.12.2).