Flat dowels

So many names

Flachdübel Lamellendübel Lamellen-Holzdübel Lamello Holzlamelle Holzverbindungsplättchen Haftlamelle Richtlamelle Formfeder Lamellen-Formfeder LFF Verbindungsplättchen Fischerl Biscuit houtlamellen …

The cheap ones made from wood

(10 cent each)

We got what we pay for

But we can do much better and even cheaper than the cheap weak wooden ones

With the standard thickness of 4 mm you will not be able to break one and the bestagons increase the glue area for much stronger binding. 

Last Meters Profile

Great idea to use the rest of filament from nearly empty spools. 
The profile prints one by one and so only the last one may fail if the spool end is reached. 

Print and sell them on etsy/amazon/ebay/or else

Print costs are ~1 cent or less each.

Regular prices for the wooden ones is 10 cent each,
plastic ones made from ABS call 40 cents each.

That is a good oportunity to make many from your printer. 

You need a commercial license to do so,  just get one from my new club.
If in doubt feel free to ask.

3 shapes, all 3 sizes (#20, #10 #0)
the hexagons are the best

They do not swell

I added this chapter because of the surprising amount of hate this model earns on facebook by miss informed people who do not know what they are talking about.

In woodworking education, when teaching the use of biscuit joints, reputable instructors typically emphasize that the strength of the joint comes primarily from the glue bond, not from significant swelling of the biscuit joints itself. Here's a breakdown based on current woodworking knowledge:

Accurate Teaching: Good woodworking teachers explain that biscuit joints, which are small, oval-shaped wooden biscuits, are used to align and reinforce joints. The biscuit joints fits into slots cut by a biscuit joiner, and glue is applied to the slots and surrounding wood surfaces. The glue forms a strong bond between the wood pieces and the biscuit joints. While biscuit joints absorb some glue and may swell slightly, this swelling is minimal and not a significant factor in the joint's strength. The primary role of the biscuit joints is to ensure proper alignment and increase the gluing surface area, which enhances the overall bond.

Potential Misconceptions: Less experienced or poorly informed instructors might overemphasize the swelling of biscuit joints, suggesting that it creates a "locking" effect or significantly contributes to joint strength. This is misleading. The swelling, if any, is slight and mainly helps the biscuit joints fit snugly in the slot during assembly, but it does not provide substantial mechanical strength. The glue's adhesive properties and the wood-to-wood contact are what hold the joint together.

Learn from the pros:

https://www.wwgoa.com/search?s=Biscuit+Joiner

Inspiration

https://lamello.com/de/produkte/lamello-system