Hola! Welcome!

Box sets fit well in these.

Golden State Art, Pack of 100 11 1/4 x 14 1/8 Clear Bags for 11x14 Mat Matting

Any Ultra Pro or BCW Magazine size bags and boards will store modules well. They are about $30 for 100 of each.

I have purchase those plastic boxes off ebay, the thin, folded flat, storage boxes. They are supper tight. They are good for display, but you wouldnt want to take the box out once its in.

Edit: Changes $300 to $30. :)

Great, thank you for the magazine bag and board suggestions for modules.  That would seem to work and I know those are relatively easy to find from various vendors.

The Golden State Art Clear Bags appear to be made out of polyethylene, and though they would certainly fit box sets, I worry about long term storage.  Have you had any problem in that area?  Is there a known mylar option?

Thanks for the welcome!

Thanks for all the direction.  I spent a good deal of time sifting through threads old and new and gathered and condensed information I found useful from the fantastic collectors here who shared their practical knowledge.  I am listing it here as it might be a good starting point for the next new collector.  It should save them time following dead links at the minimum.  This is the common advice I pulled from multiple threads.  Don't consider this list the be all end all on how to store and preserve your collection.  Just a good start hopefully!

GENERAL BAG SIZE GUIDELINES:
-        Mylar preferred in all instances.  Polypropylene bags will deteriorate in 3-5 years and will need to be replaced.
-        Regular comic bags (Traveler and OD&D)
-        Silver Age comic bags (Wizard’s Spell Compendium)
-        Thick Magazine sized bags (Modules and most accessory books) 8 7/8” x 11” is what you want.
-        Sheet Music sized bags (Hardcover and large softcover books and thin box sets)
-        Treasury sized bags (Small Box sets – Basic, Expert, and Spelljammer)
-        Life Magazine sized bags (Mid – sized Box sets – Council of Wyrms, Hellbound, Return to Tomb of Horrors, Nights Below)
-        Maybe a ziplock bag for large – sized Box sets like Menzoberranzan and Planes of Conflict & Law)
-        Suggest bagging and boarding all modules and magazines at a minimum.  Some board HCs as well.  

Calcium buffered archival backing boards.  Shiny side should be facing the product.  That is the treated side and will absorb acid.  
A suggestion to stuff box sets with large bubble wrap to prevent the lid from cupping.
Wood Grain Box Storage: Clear Lid Boxes with Clear Case  uline.com/Product/Detail/S-10578/Retail ... -5-3-8-x-1   Otherwise store flat to avoid shelf wear, maybe bag the books separately with acid-free boards.
Book Storage Bags but not Mylar - https://www.bcwsupplies.com/10x13-book-bags

LONG TERM STORAGE:
STERILITE 32qt gasket boxes.  Have larger sizes.  Some have groves to hold hanging file folders which you can use to hold 4 or 5 modules each.  Can line boxes with cardboard as these boxes have a ridge that runs along the bottom.  This would prevent damage of stored materials.
The 66 qt / 16.5 gallon STERILITE box holds hardcovers upright.  Goes on sales at Target for $5.99 at times.  target.com/p/sterilite-66qt-clearview-l ... nk=sametab
Store books by standing them up in the box or tote.  Do not store spine up or down.  It can shift the text block.
This Storex Portable File Storage box holds 40 modules, stackable, keeps light out.  amazon.com/Storex-File-Storage-Transluc ... amp;sr=8-8
Box set storage (about 3 can fit in these): Gaylord Archival Flip-top Document Case  gaylord.com/Preservation/Document-Prese ... p/HYB02293

SUPPLIERS OF BAGS, BOARDS, OR STORAGE BOXES:
Bags Unlimited: https://www.bagsunlimited.com/
Ultra Pro: https://ultrapro.com/
BCW: https://www.bcwsupplies.com/
EGerber: https://www.egerber.com/
Bill Cole Enterprises: https://bcemylar.com/
Light Impressions: http://www.lightimpressionsdirect.com/archival-boxes/
Container Store: https://www.containerstore.com/welcome.htm
Clear Bags: https://www.clearbags.com/ - 16 ¼” x 20 1/16” + flap, Crystal Clear Bags [B16S]; 17 13/16” x 32 3/8” Premium Protective Closure Bags [PEC4080].  Use these for larger box sets.

I have bought bags (including Mylar) from Mega City Comics in Camden which is always a fun trip. I think more recently I ordered them online.

For longer term storage, I use Really Useful Boxes which you can get from any Rymans

Really Useful Boxes | Really Useful Storage Boxes | Ryman® UK

Using backing boards and sometimes mylar to protect items inside. For any older, rarer, box sets I will unpack the contants and store them separately - but generaly I don't and I do wonder if, over time, the contents bend and sag if the boxes are stored upright.

Not sure we can do slabbing here. Honestly, I am on the fence if third party grading is for me, but I was intrigued and called the CGC office in London. They told me that they do not take submissions for games and said that instead I post whatever parts of my collection I want graded to some CGC office in the US (making sure I cover import duties etc.. ), to which I thought, errm, thanks but no thanks :lol:

The 10 x 13 are great for hardcovers with it handling even the largest ones like the 2E monstrous books.

-SKA