There are several anomaly-like...er...things that I think don't quite qualify for the official anomaly list. However, they do deserve a mention, so here they are. Any others you can think of? E-mail me. You'll be given full credit.
*Ep: Elogium, first season.
No.: Tough decision this. It's made up of million of creatures, but to begin with they thought it was a single nebula so...1.
Desc: At first looking like a pink nebula, closer scans then show it is in fact millions of pink sperm-like life forms travelling together. The beings flagellate to move, and all have an incredibly high metabolic rate.
Relevance: The creatures accelarate Kes' sexual maturity, and get the crew thinking about sex, pregnancy, families...cheesy but great.
Running Total: 1.
*Ep: The Swarm, third season.
No.: Again, like 'Elogium' it looks like one huge anomaly. But again, it's made up of millions of objects. So 1.
Desc: Appearing as a light brown cloud, it soon becomes apparent that it is made of millions of small green/brown ships.
Relevance: Voyager needs to pass the swarm to get home. This ep also really starts the Paris/Torres romance, for those keeping track.
Running Total: 2.
*Ep: The Gift.
Desc: In the first case, Kes can see into and beyond the subatomic (majorly cool) Lots of different colours. In the last two she breaks things down to their molecular level (Voyager and then herself). This effect is white or pale blue.
Relevance: To display Kes' growing abilities so she can leave the ship.
Running Total: 5.
*Ep: Day Of Honor.
No.: 1, used twice.
Desc: Random ion turbulence. The turbulence itself is invisible.
Relevance: B'Elanna and Tom encounter the turbulence in their space suits so their oxygen supply can be depleted. Thinking they're going to die, B'Elanna tells Tom she loves him.
Running Total: 6.