Hmm... for some reason I love this page, but the description is one of those long, rambling, disjointed ones that's obviously been written and added to by many different people. So I think I might try to sort out the various stock types of sequences:

• Magical Girl: Our heroine usually utters a key phrase, accompanied by certain gestures and/or using some sort of magical device, and then hovers into the air over a magical background and has her clothes disappear as her hero costume glows into existence over her until all her ribbons, jewels, feathers and assorted frippery have formed. Despite being strongly associated with Magical Girls (Sailor Moon could be the Trope Codifier) there are several 'magical boys' who have comparable sequences, though their outfits are usually more like uniforms or armour.
• Henshin Hero: Similar to the Magical Girl but usually less elaborate and more awesome, our hero uses his special device (often a weapon) and/or shouts his transformation phrase to turn into his superhero form in a faster but equally flashy sequence, that for some reason often involves lightning, glowing or shining, and the hero announcing himself.
• Super Mode: An already-powerful hero or villain becomes even more powerful to face the latest threat. Usually a toned-down yet more intense kind of sequence, with the raised power level indicated by a colour change, glowing eyes (or hair) or appearance altered in other ways.
• Monstrous Transformation: A darker and more physical sequence, usually when a humanoid character becomes more monstrous before our eyes- often involving bulging muscles, ripping clothes, (to various extents) and often implications of pain, especially in a horror-themed series.
• Mechanical Sequence: A Humongous Mecha or Power Armour wearing hero gets into battle mode, whether through transforming, combining, adding the gear, and/or just plain launching into battle. Usually contains as much Technology Porn as time and budget will allow.

...that's the main ones. Does Make My Monster Grow count?

Deleted the picture- it wasn't a very good image in terms of representation, and it had a giant white spot in it for some reason. Open to replacements.