I've been using Campfire Pro for some time to organize timelines, characters, and more for two different series that I've been building the underlying foundations for. The first is "Magic Realms" and the main one that I've been building is my "Drifters" series.
If you've never used a writing aid program, your first question might be, why not use something else like a stand-alone word processor or other utilities like a spreadsheet program? The answer, I did, and it gets confusing. The Drifters Excel spreadsheet that I had been relying on has 13 different pages and the longest of them, the Characters page, has 82 different unique characters which isn't even all the characters that appear in "Drifters: Origins." All this doesn't include the different word documents scattered across my computer that contain other information pertaining to the series ...
That's why, for a long time prior, I was seeking a program that would allow me to begin placing all this into one single convenient place. Campfire Pro, with the Worldbuilding Pack allows me to put things into massive timelines, chart character relations, bios for every single character (including those that only appear once), and more into a single cohesive thing. This has already proved invaluable in the lore I'm mapping out for my second novel, "Drifter: Grand Tournament Games."
Does it have flaws? Of course. No program is perfect, but Campfire Pro has come the closest to having everything that I need in a single program that I can own outright and keep entirely on my own machine. The latter is extremely important because it means that I'm not reliant on always on internet connections and can continue working even when the internet goes down or safe wi-fi isn't available.
So, my final rating on Campfire Pro with the Worldbuilding Pack is, unless you haven't been able to tell from my title, a hearty "Must Have."
You can find out how to purchase it on their website at: https://www.campfiretechnology.com/
Be sure to also check out Campfire Blaze, their new online utility that has even more features than Campfire Pro and is still being expanded.