Here are a few thoughts - and I would think about this in the context of what you are hoping to accomplish. These are supposed to be leading indicators of your marketing, so I like to look at things like

• Organic Traffic Growth
• The conversion rate on the site
• Size of your MQL/SQL list that you can nurture
• Deals/Opps that marketing helped create

But, this really comes down to details about your b2b industry. i.e. deal volume, velocity, and the organizations you are selling to. 

mkingery@(PRIVATE).com

maria kingery - she is an eos client and has become an implementer - 

email her tell her Walt sent ya

A different twist to some of the standard marketing metrics like website leads and traffic is to add "Ideal Client" to the beginning. In the B2B space, If your Ideal Client/Target market is well defined, you probably have (or can get) a pretty good idea of the establishments that meet that ideal client criteria.

Another more salesy metric is the sales stage conversion rates as Debra Chantry-Taylor76 pointed out. There is a downloadable spreadsheet in the blog linked below that you can use to calculate the impact of improving the various stages of your Sales Process.
https://www.convergo.co/sales/how-to-move-needle-on-most-impactful-pipeline-metrics/122