There are lots of websites out there for the card collector today. It wasn't so long ago that there really wasn't such a great resource. Now you have checklist sites, Beckett, Zistle, various forums, user groups, Facebook groups, and my favorite The Trading Card Database.
I've been using the database since it pretty much started back in 2008. If you've never checked out the site, I'd give it a go. I won't say it's the best site for inventorying your collection, but you could and since 2008 the site has been and continues to be a work in progress that is updated and corrected mostly by the users.
I've made it one of my personal goals to try and update, correct, add information and add as many images I can find for Robin Yount on the site. The website is free and it's checklists are printable, so if you're looking for a full set checklist, a team checklist, or a player checklist it's a great resource. Since the website is free the site is maintained by ad revenue, member contributions, and page sponsorships. That being said The Yount Collector is now the proud sponsor of Robin Yount's player page on the website.
I'm not shilling for the website, but sponsorship is only $5 a year. So if you use the Database and have a team or player or even a set you love you can sponsor it. And you get a link to your blog or website.
I'd also like to ask if you are a fellow Yount collector and have cards, especially rare ones, squirreled away somewhere to maybe think about scanning them and submitting images to the database.