So, I've been using a Tracfone smartphone for a couple years, bought the phone cash at a computer swap meet, bought the bring-your-own-simcard cash at a Walgreens, and have used physical refil cards bought cash since.  

Except now ... I am having trouble finding 1 year extension cards. I don't use it frequently, but I will shell out $100 a year to maintain the number and then by 30 day data/call/text cards when i need them.

But I want to buy cash. So far, it has gotten very hard to find these physical cards.  

Anyone have a better strategy? Any of the other prepaid vendors do better at this? Really would like having to register online or any such thing.

Buy refill card with cash, but I haven't seen one-year cards. Just fill it when I need it.  Can you use a gift card visa to buy one year online?

Yeah, I've thought about that; I am also thinking about finding the cheapest monthly I can find and use a visa gift card to do that. But you then have to register a fake name, yada yada to use the visa gift card.  

Cash is just so much easier. I can by refill cards and do it each month, but you have to remember to do it so you keep your number (a lot of my screening is of course tied to my number). And it can be pricey if you are not going to use the phone for a couple months.

I also use tracking, but have never noticed a 1 year card at a retail store. I know that you can use a Vanilla gift card on tracfone's website. Seems like your best option if you don't want the hassle of monthly plans.

I have been using TracPhone for years.  I pay cash at Target.  Maybe once over the last 10 years, were they out of stock of the 1 year extensions ($99).  I got a 3 month one, then got a 1 year one later.  TracPhone is now owned by Verizon, so they will be around for a long time.

I bought the actual phone at Target, then bought the 4G upgraded model at Target last year.  
They can transfer your phone number to the new phone by swapping the sim card.  
Your phone number is key to all the provider orgs to identify you, so keep it

Shop around.  The great thing about burners is there is no connection to our real life.  

Have used GV since Apple stopped supporting the Burner AP CoverMe.  I am satisfied with Google Voice so far.  A
Re there any downsides?

I have been using Tracfone for many years. Like you I bought yearly refills from Walmart. In the last year or so Version bought Tracfone and I knew it would not turn out well for guys like us. I bought enough yearly refills to cover me until 2024. Hopefully some type of untraceable payment method will be available by then. Following this thread with interest.    

I first purchased my burner at the beginning of the month, so its refill date is predictable. Even so, I get an alert 5 days prior to it expiring. Mileage varies on particular phones or plans as to whether or not they have that feature.