@Amjad_Sahi - both Rider and Visual Studio for Mac report that this class is missing.
https://apireference.aspose.com/net/cells/aspose.cells/pdfsaveoptions
I’m referencing Aspose.Cells in a netstandard2.0 library - below are some screenshots showing the issue:
The assembly reference:

aspose-cells-pdfsaveoptions_5.jpg (32.6 KB)
Missing reference error in Rider:

aspose-cells-pdfsaveoptions_2.jpg (16.2 KB)
Rider intellisense also cant find it:

aspose-cells-pdfsaveoptions_3.jpg (47.6 KB)
Project reference in net standard 2.0 library:

aspose-cells-pdfsaveoptions_1.jpg (78.8 KB)
Visual Studio for Mac showing class missing in Assembly:

aspose-cells-pdfsaveoptions_4.jpg (89.0 KB)
The nuget cache for Aspose.Cells:

aspose-cells-pdfsaveoptions_6.jpg (18.8 KB)
Missing from XML doco:

aspose-cells-pdfsaveoptions_8.jpg (203.8 KB)
Things I have tried:
- Removing the nuget package and re-adding from the project (both in VS for Mac and Rider)
- Cleaning all local nuget cache (nuget locals all -clear)
- Rebuilding the solution
- Cleaning solution
Please advise what else you need to help me diagnose this issue.