How to Make the Most of Manipulatives by Marilyn Burns
http://teacher.scholastic.com/lessonrepro/lessonplans/instructor/burns.htm
Virtual Manipulatives
Bitmoji Slide - Images on this slide link to a variety of virtual manipulatives.
Wakelet Collection - Visit this collection for a variety of links to web-based, virtual manipulatives.
DIY and Printable Manipulatives
Here are some sites that offer resources for copying or making manipulatives. Many also include recording sheets and other supporting materials to be used with hands-on activities.
Hand Made Manipulative Instructions
http://mason.gmu.edu/~mmankus/Handson/manipulatives.htm
A Math Toolbox in Every Home
http://mathcats.com/mathtoolbox/
SEN Teacher has a range of math reproducibles that can be used as manipulatives.
The Kentucky Center for Mathematics has a page of math tools. You'll find both pdf and doc resources here, as well as links to other web sites with manipulatives and downloadables.
Custom BINGO Cards
http://www.dltk-cards.com/bingo/
Dynamic Paper
This interactive allows you to create the following:
Nets – two-dimensional outlines of three-dimensional shapes, including regular polyhedra, prisms, pyramids, cylinders and cones
Graph Paper – coordinate graphs, polar coordinates, logarithmic graph paper
Number Lines – including positive and negative coordinates
Number Grids – hundreds boards and the like
Tessellations – tiling patterns involving triangles, quadrilaterals, and hexagons
Shapes – pattern blocks, attribute blocks, and color tiles
Spinners – up to 16 sectors, with adjustable sizes
Select the tab for the type of image you want, enter values for the parameters, and click Add to insert an image into the workspace. On the workspace, you can adjust the size of the image; to change other characteristics, you will need to adjust the values of the parameters on the dashboard. Once the image is created you can export it as a PDF activity sheet for your students or as a JPEG image for use in other applications or on the web.
Commercial Resources
Here are links to companies that sell manipulatives. Many of them also offer free resources and newsletters related to math instruction.