Where to find variants for banknotes?

You can start by looking in your wallet.

Nice idea
But a website

Do you want to find what variants exist? You are already on Numista! There are also Colnect and Bank Note Museum

Do you want to buy variants? There are lots of dealers posting variants for sale.

Will

Yes
But like this thread
https://en.numista.com/forum/topic106012.html

I asked for help re: info on pre-Euro banknotes to collect here. A member on another forum posted that it would be wise to look out for short dates issued for French notes, and single vs double letter prefixes on Portuguese & Spanish issues. This rule also applies to banknotes from the Philippines so that single letter prefixes are much scarcer than double letters, such as this 200 Piso:

Any note that undergoes a design change is a must for me. There are many & this P-157 50 Francs is a great example. A few modifications were applied to P-157A so the former is more desirable. Many collectors go for first prefixes (especially Great Britain) but I like to find out which were short & sometimes the last prefix is preferable.

Numista has been very helpful in finding info on currency that is less common. I also look for notes that have had security strips added & try to get the earlier version. I have found Bank Note Museum very helpful in narrowing down which notes (tougher variants) I want to acquire.

As a general example:
If you look at Canada's P-101 you can see that the prefix AOF had a run of 3.8M vs the typical 10M prefix & Numista provides frequency so you will see that only 1.8% of the entries are of this prefix -thus tougher & more collectible compared to P-101A. However prefix APM (with security strip) is actually less common than the AOF as it was a short prefix (less than 0.5M). It takes time to really get to know what is collectible.

For more expensive collectible banknotes discover how the nation's bank designate replacements (Z prefix for many countries) & these are excellent variants to collect also IMO. I also tend to gravitate towards lower serial numbers & higher grades.

I find Bank Note Museum http://www.banknote.ws/ to be very helpful. If you go to a listing for which there is a similar note, they will show you a link to the similar one.

Citeer: "Steve27"​I find Bank Note Museum http://www.banknote.ws/ to be very helpful. If you go to a listing for which there is a similar note, they will show you a link to the similar one.

​-Yes, "Steve27" I use this site regularly.

As an example, when I was looking for pre-Euro & Belgium notes I noticed this P-140 100 Francs had been only 3 years in circulation before it was modified to P-142 with signatures printed on both sides. I like the way there's a link to the later versions & they list all signature variants which is helpful for notes from Portugal & other nations which use several signature combinations. Obviously the second version lasted 12 years & will have more variants but the initial version were much tougher to acquire. I found about 1 out of 12 auctions were for the first version on eBay & most of these older versions were listed near BV while the 2nd version was much cheaper (in fact I even found one newer P-142 was incorrectly listed as P-140).

I cover paper money collecting strategies on my Notaphylic Culture site with weekly updates. I also include a Notaphylic Sites page with many useful online resources.

Thank you