Many hoodoo formulas are related to one another, sometimes very closely. Some formulas, Lovers formula versus Love formula, are just manufacturer specific names for what is essentially the same product (or at least a product meant to get the same result.) Sometimes people wonder, what's the difference between Uncrossing and Van Van? What's the difference between Road Opener and Blockbuster?
First things first: Road Opener, aka Abre Camino, is not a traditional hoodoo formula, it's a Latin American loaner that has come in relatively recently along with a lot of Santeria and Brujeria practices. This is why it seems to cover the same ground that several other old hoodoo mixtures do. Blockbuster might also be in this same boat, though my evidence on this is less sure -- nonetheless it does seem to be a newer formula, and often sold with an alternate Spanish name "Arrasa con Todo."
Van Van and Uncrossing are more authentic old-time hoodoo mixtures, which traditionally are used for much the same purposes as the above mentioned. In old style hoodoo thinking, blockages are caused by crossed conditions, so Uncrossing would be used to remove them. Additionally, Van Van had the power to not just remove negativity but also draw in fortunate situations, something like Road Opener.
While the recipes are separate, we can pretty much say Van Van and Road Opener have the same basic intention. Road Opener is probably more popular these days since it's typical in modern hoodoo that we expect conjure formulas to have a name that describes what they do -- Older formulas, meanwhile, often deliberately had names meant to obfuscate their purpose so as to avoid legal repercussions. Van Van is fairly nonsensical as a word, though it's been suggested by Cat Yronwode that it comes from the word vervain, which is sensible as proper Van Van always contains lemongrass, which in the old days was sometimes sold as verbena/vervain oil due to its similar scent to lemon verbena. Nevertheless, vervain is only helpful as a designation if you know what to use it for. Road Opener makes it much more apparent what the mix is meant to do, so it's surpassed the old Van Van in popularity.
Blockbuster and Uncrossing are both able to make their intentions clear from the name alone. Uncrossing seems to be the more popular of the two formulas here -- it's certainly sold much more frequently. Uncrossing is used to end crossed (cursed) conditions. Blockbuster, meanwhile, is meant to remove blockages, but it lacks the suggestion that the blocks were deliberately put there or that they're part of a curse. Modern thinking tends to assume a certain amount of struggle will be present in daily life, whilst older thinking apparently attributed all troubles to evil conditions placed by enemies. So basically, Blockbuster is there for those who have chronic problems that are unable to be solved by natural means, but don't feel they were caused by a 'curse' deliberately placed.
It's also worth noting that The Black and White Magic of Marie Laveau seems to use Special Oil #20 in places where we'd now use Blockbuster. There's also a formula called Arabka Soudagar which is another modern mixture, probably evolved from a brand of incense from India (the name seems to come from the Hindi for "Merchants of Arabia" -- probably meaning to suggest exotic perfumes) which is used as a road opening type blend as well.
So basically we have these related formulas: Van Van, Road Opener, Blockbuster, Uncrossing, Special Oil #20 and Arabka Soudagar.
Van Van, Road Opener and Arabka Soudagar all are said to be able to remove bad luck and blockages, and also draw positive influences and good luck.
Special Oil #20 is said by some to be an all-purpose mixture, but it seems to have a definite emphasis on blockage removal and solving of stubborn problems. Blockbuster is also commended for removal of blockages and recurring problems.
Uncrossing is intended specifically for removal of curses and problems which have been caused by them. Other formulas with names like Jinx Remover, Spell Breaker, Reversing, etc. also share this basic purpose.