I use Numbers on MacOS, Excel like.
I have one main spreadsheet that I track everything I currently have active, including columns for name, extension, type (e.g. 1 word, acronym, 2 word etc.), registrar, current expiry, first registered, columns for reach marketplace I use (Afternic, Sedo, DAN, Epik, Namecheap, NameSilo, Dynadot, etc.) with an O for offer, F for fast transfer, B for Buy-It-Now price etc., the total price I have paid up to now (i.e. acquisition and all renewals), my BIN price, automated appraisals for GoDaddy, Estibot and NameWorth if available, and a notes text section for various comments.
I can order that by say expiration date to see what is coming up, or extension, or most of the time just name.
I have separate spreadsheet "pages", for sold domain names and names I let expire. I keep less information on those, but for sold as well as name I have where it sold, date, gross, commission, net and notes.
Separate from all of this I have a huge Wish List spreadsheet with a page for each extension I have considered carefully domains in and a line for each domain name. Mainly name, status, automated appraisals, notes on things like TLDs, Google search. Open Corporate businesses with that name, search volume, advertiser stats like CPC, related TM if any, past history, etc. It is in a very condensed code that probably only means anything to me.
28 TLDs, com fs $12k .net av, 4 dr; 122 ac OC; 45M res " " 98k; 8.7k ex $0.65; 1.2M br $1.31; 2 ad; .org sold $900
That all means that the exact name is registered in 28 different extensions
The com of it is for sale at $12,000, while the .net is currently available
Name has dropped 4 times in past according to HosterStats or DTs
There are 122 active company listings on Open Corporates for the term
Google simple search on term has 45 million results, but when I put it in quotes it is 98,000
There are 8700 exact search with $0.65 CPC, but 1.2 million broad at $1.31 CPC with Estibot showing 2 ads
The .org of the same name has a sale at $900 on record.
Probably TMI.
It keeps me busy so I don't register too many domains I should not!
Bob
PS I also am very old school and when I buy or sell or renew a name I write the brief particulars in a physical notebook. I know, so old fashioned!