I have been using Contacts+ since 2017.
It’s not a Personal Relationship Manager per se, but a piece of the larger puzzle. It keeps all the different address books you have in sync. So as you create new contacts or update existing ones, you don’t need to worry about where they are stored, and Contacts+ synchronizes them for you. It also detects duplicates and helps you merge them, and gets updates from social media to keep your contacts fresh.
It can remind you of birthdays. That’s about as far as it goes as a PRM.
Nothing shiny, even a bit outdated, but, on the upside, you seldom see it.
It works in the background, almost impossible to detect.
Contacts+ comes with iOS and Android native apps, a web app, a macOS native app, and a Chrome extension making it available everywhere.
It connects with Google Workspaces, Office 365, and iCloud for contacts synchronization. It also works with Zapier and Blendr for more automation.
Contacts+ is very specialized; it does just a few things but very well.
Free for a single address book and up to 1,000 contacts, which is of limited use. $9.99/month or $99/year for up to 5 accounts and 25,000 contacts.
I have been using Contacts+ for more than five years, so I can only recommend it.
Yet, I almost forgot a key feature, and the reason I originally installed it: it is a great business card scanner, saving much time when traveling was a thing.
I’d get back from conferences with many of those. I have not used that feature much in the past two years, I’ll admit.
Overall, it is a great tool if you are serious about managing your contacts, but it is not sufficient by itself.