I don't have the time or inclination to create lists. So lets try it again. Suppose you go to the casino to play a slot machine. You get a handful of tokens and choose your machine. Each token is potentially sufficient for making you into a winner, and if you win, the token that won will have been sufficient for making you a winner, but there is no way to know beforehand exactly which one it will be. You only know that given enough tokens, the more you play the more likely it is you will win, and the clear disctinction will be when you are either broke or a pile of cash lands in your lap.
That's actually a pathetically poor analogy for whether or not the evidence for UFOs is sufficient.
If I go into a casino with a bucket of coins to feed into a slot machine I can be pretty certain that at some point I will win some money from at least one of those coins. In fact, I can know,
a priori, what my chance of any one coin winning will be. This is because we can know the settings of the slot machine. Yes, it's possible with only a handful of coins that I won't win, but I know that it's both possible and likely that I could win at least a small amount.
With UFOs we have no real idea whether or not any sighting is of a genuine alien craft. They could be, or there could be no such thing and all UFOs are actually misidentified mundane things or hoaxes. There is no
a priori knowledge of whether or not there's a chance of "hitting the jackpot".
I present you with two slot machines and a handful of coins. I tell you that the machine on the left pays out on average $10 for every $20 that you put in it, and that if the one on the right pays out it could possibly pay out $1,000,000,000, but there's a chance that it will never pay out anything at all.
Which machine would you play, and for how long?
In what way are the two slot machines comparable?
The second slot machine is the one that is equivalent to the UFO situation, except that we've been feeding it coins for a while now, and no sign of any payout yet.