User can sense the presence of energy, whether they are electromagnetic (magnetic/infrared), psionic, magical, spiritual, etc. and possibly gain detailed understanding about the energy they are sensing, including the amount/size of energy they are sensing and whether it is hidden.
The Z-fighters (Dragon Ball Z) sense Future Trunks's Super Saiyan ki.
As a sensor-type shinobi, Ino Yamanaka (Naruto) can detect the presence of other people by directly sensing their chakra.
Karin (Naruto) can use her unique sensory ability, the Mind's Eye of the Kagura, to track any targets through their chakra signature.
Gyokuro Shuzen (Rosario + Vampire) using Enemy Zero...
...to sense and track any and all monster energy within a several thousand mile radius.
Kenbunshoku/Observation Haki users like Monkey D. Luffy (One Piece) can detect the "intent" of any living creature.
Knuckles the Echidna (Sonic the Hedgehog), can sense the chaos energy of the Chaos Emeralds, the Master Emerald, and similar objects like Sol Emeralds, and can track down their "signals", making him a living Emerald Detector.