Salesforce: Functions versus Rules matrix

As Salesforce admin, function is one of my favourite feature, you can use it in:

• Approval Entry Criteria
• Approval Step
• Assignment Rule
• Auto-Response Rule
• Custom Button and Link
• Escalation Rule
• Field Update
• Formula Field
• Validation Rule
• Workflow Rule

As of Summer'15 release, there are more than 60 functions available, not to ask if you have use all of them, but do you aware if they are exist? I never know and use EXP, LN, LINKTO, SQRT and a few more, and hardly use ABS, BR, DISTANCE.

Do you also know, some of the function only available in certain area, such as:

• HYPERLINK, IMAGE only in Formula Field
• VLOOKUP only in Validation Rule
• FORMAT_ADDRESS, GETRECORDIDS, and a few more only in Custom Button/Link

I try to summarize functions available in each area:

Click here to download the Excel file. Let me know if I missed any or wrong information shared.