Hey here is the list of some awesome CSS code generators, I am not going to explain what each sites do, explore these sites you can find many useful resources from these sites.
The below mentioned links will help you to generate and design CSS3 Buttons, definitely a time saver. Almost all sites have same functionality, some do have collections to choose from, bookmark which you like the most. You can learn from playing with the parameters.
Here is the short list of spinners I found useful.
Here is a list of useful CSS color gradient generators.
You can check more web development resources below.
Please share your favorite resources and also if there is any mistakes or areas need improvement, point it out. Thank you and happy coding :)