Some show commands which might come in handy.

EIGRP

show ip protocols
show ip eigrp neighbors
show ip eigrp topology
show ip route eigrp
show ip eigrp topology all-links
show ip eigrp interface

show ipv6 protocols
show ipv6 eigrp neighbors
show ipv6 route eigrp
show ipv6 eigrp interface

CDP

show cdp
show cdp neighbors
show cdp interface
show cdp neighbors detail
show cdp traffic

LLDP

show lldp
show lldp interface
show lldp neighbors
show lldp neighbors detail
show lldp traffic

Port-security

show port-security
show port-security interface type number

STP

show spanning-tree
show spanning-tree active
show spanning-tree brief
show spanning-tree detail
show spanning-tree interface interface-id
show spanning-tree vlan vlan-id
show spanning-tree summary

Miscellaneous

show mac address-table
show interfaces
show vlan
show interfaces trunk
show interfaces fastEthernet 0/15 switchport
show spanning-tree summary