Here are two Medkit paper models from the game Half-Life series, created by Evgeniy Pelevin. Below is another one, the smaller, but just as useful, healthvial.
The Medkit (Med Kit, Healthkit, Health Kit) is a healing item, often found scattered around high-risk areas where immediate medical attention might be needed to prevent death.
In Half-Life, the amount of health medkits recover depends on the difficulty level set in the game’s settings. In easy and medium mode, medkits will recover 15 health. While in hard mode, medkits will heal 10 health.
The small amount of health medkits recover means that players will more often be using chargers to recover a lot of lost health, especially in hard mode.
In Deathmatch Classic, medkits come in two forms: small and large. Small medkits are a first-aid spray and bandage that heal 15 health each, while large medkits are a dirtied, scarred version of the Half-Life medkit which heal 25 health.
In Half-Life 2, healthkits always give 25 health, regardless of the difficulty setting, making them the main source of healing throughout the game, as they’re much more common and widely dispersed than health chargers, which are often only found in Combine-controlled areas. Healthkits are also found more prolifically in supply crates in more remote areas, making them more accessible when traveling between inhabited regions, such as through the Wasteland.
Similar to its counterparts in Half-Life, the healthkit has a predominantly white coloring and is labeled with a red medical cross. Their appearance is overall similar to other such medical devices, making them easily identifiable. Whereas in Half-Life they are apparently manufactured by Black Mesa, these healthkits are produced by the Combine.
The healthvial is smaller than a healthkit, and give 10 health. They are often dropped from Overwatch Soldiers upon their death. They can be convenient during battles when other supplies of health cannot be found.
Both the healthkit and healthvial contain what appears to be raw flesh suspended in green liquid, looking like the liquid in scientists’ syringes from Half-Life, presumably the material used for healing. [Source: wikia]
You can download these paper crafts here: Half-Life – Medkit Free Paper Model Download