Witchery provides you with the ability to make custom brews, which are often skipped over by many players. However they can offer you some awesome advantages depending on what you need them for. Here are a few of my favourite example brews that I personally make heavy use of.

NOTE: You must have an altar with enough power in range of the Witches' Cauldron to create brews.

These brews are order sensitive. Any ingredients marked with a '*' are optional however any ingredients with the same number of '*' must be added in that order. (example: *glowstone must be added before *blazerod, but you do not need either to add **redstone).

Brew of Combustion - This simple brew makes excellent fuel for anything that uses fuel, such as furnaces or generators. You do not bottle this one.

Mandrake
*Glowstone
*Blazerod
*Attuned Stone (Charged)
Charcoal

Brew of Tidal Hold - Pushes away water. Good for mining clay. I find this to be good enough just as is.

Mandrake
Sand
Water Artichoke Globe

Brew of Endless Water - This is the most useful brew to create ASAP. It is a reusable water bucket, and it fills the Witches' Cauldron in one go rather than requiring 3 buckets like normal. Make sure to use as many optional ingredients as you can afford, it saves you in the long run. You do not bottle this one. (Tip: Snowbells drop snowballs, making this an easy potion to craft.)

Nether Wart
*Glowstone Dust
*Blazerod
*Attuned Stone (Charged)
Snow (block)

Brew of Speed - This is a pretty simple brew, just boosts your speed. I rarely go past Blazerod and redstone as far as the optional sections go.

Nether Wart
*Glowstone Dust
*Blazerod
*Attuned Stone (Charged)
**Redstone
**Obsidian
**Minedrake Bulb
Sugar

Brew of Jumping - This brew helps you get around. I count the glowstone dust as required as that is required to jump 2 blocks high.

Nether Wart
Glowstone Dust
*Blazerod
*Attuned Stone (Charged)
**Redstone
**Obsidian
**Minedrake Bulb
Leather

Brew of Floating - Another mobility brew, quite an interesting one. It makes you float just above the ground. The more power you add (marked with just one *), the higher you float and the slower you float back down. Really helpful when building, or when you want to skim across rough terrian quickly, I have learned to not add duration to this one, as unless you have milk or a remove possitive effects brew you are stuck in the air until it runs out. Stopping at Glowstone Dust is good enough most of the time, and lets you get over 2 high walls.

Nether Wart
*Glowstone Dust
*Blazerod
*Attuned Stone (Charged)
Sugar Cane

Brew of Pulling - This brew pulls things towards you, removing glowstone just pulls things to the splash location (assuming you do not use anything marked with *), while anything marked with ** increases the pull area.

Nether Wart
Glowstone Dust
*Blazerod
*Attuned Stone (Charged)
Slimeball
**Wood Ash
**Cocoa Beans
**Wispy Cotton
Water Artichoke Globe

Nether Panic - This is one of my more complex brews, and one I have carefully designed. The purpose of this one is for when mining in the nether it is a panic button brew, it protects from lava and fire, clearing it away and giving fire resistance. I do not compromise on this one unless I absolutely can not afford a component of it.

Nether Wart
Tear Of The Goddess
Glowstone Dust
Redstone
Magma Cream
Glowstone Dust
Wood Ash
Cocoa Beans
Water Artichoke Globe

Brew of Shifting Seasons - This particular varient lets you convert a 3x3 area to the biome of your choice. Perfect for bees. Adjustments can me made to create a larger area by increasing the power, or a 1x1 by cutting out the glowstone dust.

Nether Wart
Tear Of The Goddess
Diamond Vapor
Diamond
Glowstone Dust
Biome Page (This determines the biome, simply flip the Book of Biomes (Extended Edition to the the desired page, then craft with a single piece of paper)
Water Artichoke Globe

You can also create your own brews for whatever needs may arise.