You're right, the options are getting fewer.
As a caution to those unfamiliar with the appropriate application of amplifiers in an OTA TV antenna system; In many cases an amplifier is not needed, and the use of of one may result in less reliable reception due to overloading. This is especially true of high gain amplifiers. Channel Master states the following on their web site, "An ideal scenario for the Titan 2 High Gain Preamplifier is an application where ALL broadcast towers are 80+ miles from the antenna location and a splitter is used to distribute to multiple televisions. A single high-power signal from closer proximity may cause over-amplification resulting in signal loss."
A scenario in which a high gain preamp would have useful application would be where all signals in the air are predicted to have NM (noise margin) values in the teens or lower. Also, the antenna chosen is the highest performance available and it's mounted in a location that actually has receivable signal present. If a person hopes to use a small antenna and a high gain preamp, they should be prepared for disappointing results.
Reliable reception starts at the antenna (using the correct one), it's location and aim. Amplification of a poor quality signal does not improve the quality of the signal, any more than a pump can clean dirty water. That said, in the few situations that call for a high gain preamp, I can think of three options to consider...
Antennas Direct PA-18
Channel Master CM-7777
Kitztech KT-500