Is there any fallacy in the following sentence?
"No one else can come up with a better explanation, therefore my explanation is true"
Or perhaps another version:
"You cannot come up with an explanation why I am wrong, therefore I am correct".
There are a number of possible fallacies that cover this, but two apt ones are "false dichotomy," where something is presented as an either-or choice, but doesn't exhaust the actual possibilities, and "hasty conclusion," where a conclusion is reached on inadequate premises.
Like all informal fallacies, it draws its power from its similarities to a strong argument form. In this case, if there actually are a demonstrably finite number of possibilities, and the others have been legitimately ruled out, then what remains, as Sherlock Holmes said, must be the truth.
Philosopher of science Kyle Stanford calls this the problem of unconceived alternatives: we may have developed a scientific theory that fits well with the evidence available to us now; but we don't know whether some other scientific theory that we just haven't thought of yet might work better. It seems like this should reduce our confidence in our current scientific theories. Stanford's argument has been the focus of recent work on scientific realism.