During the 2021-2024 period some special mortgage programs appeared from lenders in order to generate more loans.
However, as time goes some by these programs have been removed and some are slowly fading away.

Here are some of the programs that were introduced or added by some lenders:

Lock and Shop

The lock and shop program, where you could lock your rate and shop for your purchase up to 6 months. This program quickly went away.
The problem is whenever you create a way that allows abuse of the system without any cost they will abuse it.
locking a rate costs money for the lender, so what happened was there were many locks and shops and no purchases,
so the lender quickly removed this program, as it was loosing them money.

2 -1 Buydown

This program was heavily promoted by lenders in order to have an initial lower rate, so the rate will be 2 points lower on the first year, and then 1 point lower next year.
And finally after year 2 ended then the rate will go back to the rate it was supposed to be.
I peronally do not think this program is that great, becuase there was a cost to it, whatever you saved on the payments was actually added to the cost of the loan,
so was it really great? many times what they did is the 'seller' paid for the 2-1 buydown cost on a purchase transaction, but they could have just reduced the price instead.
Anyhow, this was a program that was heavily marketed as if it was providing some magic rate, but nothing is for free.
What is interesting is i have seen some large lenders were still use this program in 2024 to promote the lower rate in their advertising.

Zero Down Purchase Loan

Usually under FHA you could go as low as 3.5% down payment, then Fannie Mae came up with a program with 3% down payment, so a specific lender decided to cover that
extra 3% but only up to a certain amount.
Therefore, 97% Fannie, 3% covered by lender as a 2nd loan but only up to 15,000 maximum when it first came out, then they reduced it to 12,500 as a maximum second.
So basically 3% provided by the lender at 15,000 turned out to be 500,000 maximum purchase price when it first came out.
However, this program is quickly going away. We have already been notified by the lender that offers it, that they are removing it.

Bank Statement Loans

Some lenders introduced bank statement loans to their programs, these have been here for long time so i'm guessing these will stay once implemented.
These types of loans are considered Non QM ( Not Qualified Mortgages), meaning they are not part of the GSE 'Government-Sponsored Enterprise'
So these are private funding loans that tend to have a higher rate than the GSE loans.
These types of loans have existed for a long time, so i doubt they will go away, once implemented most likely they will continue.

Construction / Conversion Loans

Construction Loans has been another one, but this has not been that successful so not sure if they will decide to keep these types of loans.
This program i think is quite interesting and fits a very specific type of client, however, because it is much more complex, i fear this program may fade away.
It will still be there with some lenders. Actually very few lenders offer it.

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Now, there will always be lenders that per say specialize on certain type of loans as that is all they do, but others have integrated in to their system.

Programs that I expect to continue: 2-1 Buydown, Bank Statement Loans
Programs that may go away, as there is not much demand: Construction Loans. However, there will always be lenders that specialize on these.
Programs that are gone or going away: Lock and Shop, Zero Down Purchase.

Note a simliar program to the zero down, is the DPA Down Payment Assist Program, but that is a different program in itself.
Also for construction there are FHA 203(K) Programs for construction, but those are separate from above, and different.