Archival supplies are available through distributors like Gaylord Archival, Hollinger Metal Edge, and University Products, available on Amazon in stores like The Container Store. For those unfamiliar with archival supplies, The Container Store offers a curated selection in their Photo Storage section, including boxes, folders, and enclosures.

Consider these items with links to my preferred products below:

Creating Family Archives: A Step-by-Step Guide for Saving Your Memories for Future Generations
No. 2 pencils and a sharpener
A mini spatula to carefully remove staples and photos from sticky surfaces
Archival-quality clips to replace traditional paper clips that rust
A book and document cleaner, like Absorene
A PH testing pen
Archival-quality file folders (I prefer letter-sized folders with full tabs. Order more than you think you'll need because you'll go through these quickly).
Clear photo corners
Drop-spine archival boxes to store materials flat
Vertical file archival boxes, best for letter file folders
Bankers boxes for when you have a lot of files (Paige No. 15 Miracle Boxes are the easiest to construct and the most durable).
Photo boxes with photo enclosures
Photo envelopes
Clear plastic enclosures for papers, pamphlets, family records, and small maps
Archival photo album kits
Unbuffered or buffered acid-free tissue (If unsure of the materials you're protecting, chose unbuffered).