I noticed that there is a “Filter” option to allow you to filter the tokens list of a survey.

But why is there no “Filter” option for the “Central participant database/panel”?

I have hundreds of participants and would like to see an option to filter that list by one of the standard fields AS WELL AS by fields added via the Attribute manager. This way the participants in the filtered list could be added to a survey without having to check/select each one individually.

...And in the tokens list - where there is a filter option - the "Filter" option does not allow a filter to be set on any of the user-added attribute fields. That would be nice.

Please add this as a feature request at our idea tracker.

If you are interested in sponsoring development of any such feature, have a look at www.limesurvey-consulting.com/customization/ to ask for a quote for implementing this.

If I understand your question correctly, there IS a filter/search option for the Central Participants Database (CPD), but it is very well hidden. It also lets you filter by participant.

I am assuming you are on Limesurvey 2.0+

Go to the CPD and select Display Participants. Look at the toolbar at the bottom of the grid and there is a tiny magnify-glass icon. Click on that and the modal will open where you can add criteria, including the participant table fields, as well as other attributes you added. You can add multiple rows to the criteria. Then when you run the filter you can choose to add the selection to a survey.