Tessera is a minecraft mod that aims to provide builders with more tools to assist in building.
This mod is fully clientside, and you should be able to join any servers with the mod.
Upon loading with the mod, the user will have a button within their inventory, and a keybind (G by default), which will open up the build menu.
This mod has compatability with most modded blocks, some may or may not work so I will have to manually add them if they do not get recognized.
There are 5 different tabs.
Gradient Tab:
Based on specific waypoints of blocks you set, the tool generates a gradient of specified length between these blocks, smoothly transitioning from one block, to another in terms of color. There are native options to exclude non-Opaque blocks, non-Full blocks (i.e. stairs), non-TE (Tile Entities, like furnace or chests), non-6-faced, aka blocks which don't have the same texture on all 6 faces, and non-Ore blocks.
There is also a 2D wall preview, which creates a demo gradient on a flat 2d plane, which has options for dithering, band, map, or noise. 
If you have WorldEdit installed, you can run this gradient over a selection you make
Shape Tab:
This tab has over 50 different premade shapes you can generate, with adjustable parameters. Some shapes include spheres, torus, mountain, canyon, valley, cylinder, star etc...
There is also a drape shape, which creates a flat 2d plane in which you can place points, and pull/stretch the cloth. 
This tab heavily integrates with WorldEdit, allowing the user to press a button to generate these shapes within their selection. The expression is editable as well, so if there is some parameter in which the scrollbar caps out, the user can manually change the expression value to adjust it.
Colors Tab:
This tab has a color wheel, in which the user can pinpoint a specific color, and it will return the blocks closest to that color
Palette Tab:
Automatically generates a random block palette a user can use, with a full preview on premade structures of what it would look like
This feature may or may not be replaced by preset palettes
Lab Tab:
~~WORK IN PROGRESS, MAY OR MAY NOT BE REMOVED~~
Allows the user to generate any shape they want, it starts from a base sphere, and many parameters to adjust the shape
