This post will likely be expanded and revised over the next week.
From some of the feedback that I got on the last post on astragalus, I thought that I would dive into PubMed to find additional histamine moderating herbs. If there is severe histamine sensitivity, it can make following my model very challenging. My impression is to first ignore the microbiome and moderate the histamine response, then start working on the microbiome with some histamine-tolerance having been obtained. Many of the herbs may be challenging to get for many people.
- PentaHerbs formula, Cortex Moutan and Herba Menthae significantly attenuated histamine release and prostaglandin D(2) synthesis from RPMC activated by anti-IgE and compound 48/80 (p<0.05).
- Betula platyphylla attenuated mast cell-mediated allergic inflammation in vivo and in vitro. 
- “it is suggested that the anti-histamine release effect of Saiboku-to [SST], which contains 10 herbs, may be due mainly to the effect of Magnoliae Cortex and the synergism of the 3 other herbs.” 
- SST inhibits IgE receptor-associated protein phosphorylation in the histamine release pathway. 
- aqueous extract of Lycopus lucidus Turcz. (Labiatae) (LAE) decreases mast cell-mediated immediate-type allergic reaction. 
- Amomum xanthiodes [black cardamom seed](Zingiberaceae) (AXE) inhibits mast cell-derived allergic reactions, and that intracellular calcium, TNF-alpha, and p38 MAPK are involved in these effects.
- “Amomum xanthiodes Inhibits Mast Cell-Mediated Allergic Reactions Through the Inhibition of Histamine Release and Inflammatory Cytokine ” 
- Amomum xanthiodes inhibits mast cell-mediated allergic reactions through the inhibition of histamine release and inflammatory cytokine production.
- “mast cell stabilizer. Forsythia fructus – dose dependently inhibited the histamine release” 
- “Artemisia iwayomogi (Compositae) (AIE) dose dependently attenuated histamine release from rat peritoneal mast cells activated” 
- “Stachys riederi var. japonica Miq. (Labiatae) (SRAE) also dose-dependently inhibited the histamine release from rat peritoneal mast cells” 
- “aqueous extract of Isodon japonicus Hara (Labiatae) (IJAE) the plasma histamine levels were reduced in a dose-dependent manner.” 
- “aqueous extract of Phlomis umbrosa Turcz. (Labiatae) root (PUAE) the plasma histamine levels were reduced in a dose-dependent manner.”  
- Gallic acid inhibits histamine release and pro-inflammatory cytokine production in mast cells.
- ” an aqueous extract of Dracocephalum argunense Fisch. (Labiatae) (DAAE) inhibits mast-cell-derived immediate-type hypersensitivity. ” 
- Mosla dianthera inhibits mast cell-mediated allergic reactions through the inhibition of histamine release and inflammatory cytokine production.
- The anti-anaphylactic effect of the gall of Rhus javanica is mediated through inhibition of histamine release and inflammatory cytokine secretion. 
- Anti-inflammatory effect of Poncirus trifoliata fruit through inhibition of NF-kappaB activation in mast cells. 
For more , see the publications of Tae Young Shin on Pub Med, evaluating tradition Korean / Chinese herbs for histamine and allergy impacts appears to be his speciality.