I recently designed a new series of Pocket-Tactics models meant to print standing without supports (though support may help a bit, depending on your printer calibration) and we abandoned this style in favor of a new one for the next edition (coming soon!). The models go well with our regular 18mm range, so I decided I should go ahead and post them for you rather than just let them go to waste. As with the other 18mm stuff, if you want a 28mm version, increase the size by 166.6% (that'll get you to a 25mm base and the correct model proportions).
We've set up a Patreon page for anyone who's interested in helping to fund us so we can keep making free and open sourced games like Pocket-Tactics, Wayfarer Tactics. and others, not to mention the growing catalog of gaming miniatures that you can use for whatever you want! (Psst... we take requests and commissions...)