This is a simple gridfinity holder for common dial test indicators.  There are many slight variations in them, so I tried to make a ‘one size fits all’ holder.  It may or may not work with your particular indicator, but I found it works with all the ones I've seen or tried.  The STEP file is included if you want to make modifications.  It uses a 1x2 grid.

The model shown is printed with eSun PLA+ Bone White for the base and a 1.5mm lip at the top using Polymaker PLA Pro Metallic Chrome for a contrasting accent.  This was done with a layer height modifier for the last 1.5mm.

Here's a list of what's used in the holder:

• Accusize Dial Test Indicator (higher quality)
• Neoteck Dial Test Indicator (cheaper alternative)