The People List Block is not as filterable as the People List Page but the block has two display options (grid and teaser) that are are the same as the People list page so you could build a Directory in the same display style. The block also has two display styles that look nice in small regions, name and name and thumbnail.

People List Block - Teaser

Caren Boulding

Caren Boulding

Associate Professor
Engineering
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caren.boulding@example.com     303-555-3232
Jeff Hayman

Jeff Hayman

Assistant Professor
Engineering
Office: DUAN 525 ~ Office Hours: Tues. 1:00-2:00 p.m. and Thurs. 2:00-3:00 p.m.
jeffrey.hayman@example.com     303-555-9888
Shane Mendez

Shane Mendez

Instructor
Engineering
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shane.mendez@example.com     303-555-8338
Haruko Win

Haruko Win

Assistant Professor
Engineering
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haruko.win@example.com     303-555-3345

People List Block - Name & Thumbnail

Kristi Anseth
Kristi Anseth
Stephanie Bryant
Stephanie Bryant
Mary Davis
Mary Davis
Jim White
James White