Quick test of all the animation effects with Collapse-O-Matic v 1.8.3:
[expand title="slideToggle" animation_effect="slideToggle" duration="2000"]content[/expand]slideToggle
content
[expand title="slideFade" animation_effect="slideFade"]content[/expand]slideFade
content
[expand title="fadeOnly" animation_effect="fadeOnly"]content[/expand]fadeOnly
content