Post-doc position/fellowship application - PhD limited results due to no supervisor support and small research group - explain in positive way
Don't make excuses because you weren't in a big lab. Tell what you did and what you learned, be honest about it.
Important skills that you have acquired might include


the ability to plan, organize and conduct research mostly on your own. Make sure to point out how this will help you in the position you are applying for, e.g. you will be able to plan projects,...
the ability to network with foreign researchers (if you had almost no one in your lab to work with, you maybe exchanged emails with other labs, worked with them,...?).


These are only two examples of something you might learn in a small lab that you often don't learn in a big group. Depending on your situation, there might be other things of course, but try to figure them out. Then, there shouldn't be a reason to feel any worse than guys from a big lab, who might have one or two publications more than you.