Unearthed my entire Base Set collection from my parents attic without seeing it for over 20 years!

So as the title states I found my base set collection from 1999 that came from my parents attic. Over the holiday season I went to visit my parents and walking into the living room I was met with, "guess what we found!" And I was handed my Pokémon binder. The shock on my face when I realized the magnitude of the find my parents made. I knew back during the surge in Pokémon collectibles that I had saved my collection but had zero recollection as to where it was! After not finding it in my own possession I assumed perhaps It had gotten tossed accidentally or negligently when I moved several times over the two decades. So I'm pretty positive I'll be sending some of these out for grading... several cards are in near excellent condition. Ones including the Blastoise and Machamp (still in the packaging). The Charizard has minor scratches in the background of the holo but I'm hopeful for a high grade. Any suggestions on best top loaders to buy along with soft sleeves? Seems like some of the cards are curling (which I've read is due to lack of humidity ) although it may not effect the grading, I'd like to preserve the cards to the best of my ability going forward. I havent quite considered what I'll do with the collection yet but I'm mostly likely to sell a good bit of it while perhaps maintaining a few cards after grading for nostalgia purposes. Some friends of mine (who educated me on the possible values of some) plan to go through them with me to determine possible values and which should be set off for grading. Any recommendations for an app on Android that would be good to use to categorize the cards and their value? Thanks guys and gals